This ease involves a claim for worker’s compensation benefits. Appellant Luella Mae Johnson (employee) was severely injured in an automobile accident on October 9, 1972. As a result of that accident, she was totally disabled. The matter was previously before this court in Johnson v. Skelly Oil Co., 288 N.W.2d 493 (S.D.1980), wherein it was held that employee’s injuries arose out of and in the course of her employment with Skelly Oil Company (employer), and are therefore compensable. Accordingly, the case was remanded to the circuit court with directions to remand it to the South Dakota Department of Labor (Department) for reinstatement of an award of compensation and for a determination of the amount of compensation due employee.
In an order dated March 26, 1980, Department directed employer and self-insurer to pay claimant all permanent disability compensation and medical expenses, pursuant to SDCL 62-4-3 and SDCL 62-4-1; said benefits to accrue as of the date of the accident. It was further ordered that Department retain jurisdiction to determine *132any dispute regarding the weekly compensation benefits due employee, based on her prior earnings and medical expenses.
An agreement was subsequently reached by employer and employee regarding weekly compensation, monthly home care, and reimbursement for future medical services and supplies. No agreement could be reached as to the rate of reimbursement for mileage or for the payment of outstanding medical and related expenses incurred prior to January 1, 1975. Consequently, on March 8, 1982, in Watertown, South Dakota, Department held a hearing to determine the responsibility for payment of medicals and other items incurred by employee. This hearing was continued to obtain additional testimony through deposition. Additional testimony was obtained and presented to Department and, on April 8, 1983, it entered its decision.
Department determined that employee was entitled to reimbursement for mileage at the rate of twenty-one cents per mile, and she was entitled to interest on those medical items which the supplier of medical services had charged interest upon, or, which were paid by employee or members of her family. Department denied her claim for reimbursement for lodging, meals, and travel expenses incurred by her mother during employee’s hospitalization, in the sum of $6,020.80. Department further denied employee’s claim for reimbursement for the purchase of a television and tape player, in the sum of $225.00, and for reimbursement for the purchase price of a van, in the sum of $7,281.45.
The decision entered by Department was appealed to circuit court and affirmed with the exception of Department’s denial of reimbursement for the cost of the van, in the sum of $7,281.45, which was awarded to employee by the court. Employee appeals to this court from the judgment of the circuit court. Employer appeals from that portion of the judgment awarding employee the sum of $7,281.45 as reimbursement for the van.
Employee petitioned Department for a separate hearing for the allowance of attorney fees, pursuant to SDCL 58-12-3 and SDCL 58-12-3.1. Department denied the request for attorney fees, which denial was appealed to circuit court and judgment was entered affirming Department’s denial of attorney fees. Employee also appeals the denial of attorney fees to this court.
The issues in dispute, except the claim for attorney fees, are based upon SDCL 62-4-1, which reads as follows:
The employer shall provide necessary first aid, medical, surgical, and hospital services, or other suitable and proper care including medical and surgical supplies, apparatus, artificial members and body aids during the disability or treatment of an employee within the provisions of this title. Repair or replacement of damaged prosthetic devices, hearing aids, prescription eyeglasses, eyeglass frames, contact lenses and dentures shall be considered a medical service, under this section, if such devices were damaged or destroyed in an accident which also causes other injury which is compen-sable under this law. The employee may elect to secure his own physician, surgeon, or hospital services at his own expense.
SCOPE OF REVIEW
Before we address ourselves to the issues on appeal, we first address the proper scope of review on appeal. When the issue is a question of law, the decisions of the administrative agency and the circuit court are fully reviewable. Matter of Change of Bed Category of Tieszen, 343 N.W.2d 97 (S.D.1984); Nash Finch Co. v. South Dakota Dept. of Rev., 312 N.W.2d 470 (S.D.1981). When the issue is a ques tion of fact, we ascertain whether the administrative agency was clearly erroneous. Matter of S.D. Water Mgmt. Bd., 351 N.W.2d 119 (S.D.1984); State, Div. of Human Rights v. Miller, 349 N.W.2d 42 (S.D.1984).
PREJUDGMENT INTEREST
Appellant contends that the Department and the circuit court erred when they failed *133to grant employee’s request for reimbursement of interest on all unpaid medical bills, as well as other expenditures from and after the date of their being incurred. We agree.
The empowering statute for prejudgment interest is SDCL 21-1-11, which provides:
Every person who is entitled to recover damages certain, or capable of being made certain by calculation, and the right to recover which is vested in him upon a particular day, is entitled also to recover interest thereon from that day, except during such time as the debtor is prevented by law, or by the act of the creditor, from paying the debt.
Thus, under this statute, prejudgment interest may be allowed if (1) the damages are certain or capable of being made certain by calculation; and (2) the right to recover vested on a particular day. See Aetna Casualty and Surety Company v. United States, 365 F.2d 997 (8th Cir.1966); American Property Services v. Barringer, 256 N.W.2d 887 (S.D.1977); State v. Ed Cox and Son, 81 S.D. 165, 132 N.W.2d 282 (1965).
We interpreted SDCL 21-1-11 in Beka v. Lithium Corporation of America, 77 S.D. 370, 375, 92 N.W.2d 156, 159 (1958), and held:
The mere fact that the claim is disputed does not defeat the allowance of interest. Corcoran v. Halloran, 20 S.D. 384, 107 N.W. 210 [1916]. As applied to this case our statute was construed by this court in Gearhart v. Hyde, 39 S.D. 273, 164 N.W. 58 [1917]. The rule announced in that case is that interest is allowable on damages if there exists established or reasonably ascertainable market prices or values of the subject matter by reference to which the amount due may be determined by computation. This rule seems to be generally accepted.... The reason for denying interest on a claim is that where the person liable does not know what sum he owes, he cannot be in default for not paying. When the exact sum of the indebtedness is known or can be readily ascertained the reason for the denial of interest does not exist.
The trial court affirmed Department’s decision and denied employee’s request for prejudgment interest because no interest had been charged to employee nor had any account previously' been paid by employee or her family. In Gearhart v. Hyde, 39 S.D. 273, 275, 164 N.W. 58, 59 (1917), however, this court quoted from Laycock v. Parker, 103 Wis. 161, 186, 79 N.W. 327, 335 (1899) as follows: ‘“The true principle, which is based on the sense of justice in the business community and on our statute, is that he who retains money which he ought to pay to another should be charged interest upon it.’ ” See Clark County v. Howard, 58 S.D. 457, 237 N.W. 561 (1931).
In North River Ins. Co. v. Golden Rule Const., 296 N.W.2d 910 (S.D.1980), this court held that where the amount of damages suffered by builder due to fire was never in dispute and builders’ risk insurer refused to pay the entire amount, builder was entitled to prejudgment interest from the date of refusal. In the instant action, and its predecessor Johnson v. Skelly Oil Co., supra, the reasonableness of unpaid medicals and other expenditures incurred by employee was never disputed by Skelly Oil; the company merely contended the absence of liability under our worker’s compensation laws. We hold that employee’s medicals and related expenditures were reasonably ascertainable upon their due date and employee is therefore entitled to prejudgment interest, less any interest employer may have already paid on them on her behalf.
EXPENDITURES CLAIMED UNDER SDCL 62-4-1
Employee further contends that certain expenditures incurred by her and her family during her hospitalization, which were disallowed by Department, were compensa-ble under SDCL 62-4-1. These items include employee’s mother’s expenses for lodging, meals, and travel in the sum of *134$6,020.80; the purchase of a television and tape player in the sum of $225.00; and, the acquisition of a van in the sum of $7,281.45. Employee also seeks to increase the amount of reimbursement for mileage when travelling to obtain medical services and supplies. Employee argues that each of these items, which Department denied reimbursement for, are within the suitable and proper care provisions of SDCL 62-4-1.' The circuit court affirmed Department’s denial of reimbursement of all of the expenditures considered, except for the van acquisition. This court will address the issue of the van acquisition separately from the issues relating to employee’s mother’s expenditures, the television, tape recorder, and mileage reimbursement.
MOTHER’S EXPENSES, TELEVISION, TAPE RECORDER AND MILEAGE
The circuit court affirmed Department’s determination that the television and tape recorder purchased for employee, and the expenses incurred by employee’s mother while visiting employee during her hospitalization were not compensable under South Dakota’s worker’s compensation laws. Regarding these items, such a determination is a mixed question of law and fact. Under the circumstances of this case, we cannot say that Department’s decision, or the circuit court’s subsequent affirmance therein, were clearly erroneous.
THE VAN ACQUISITION
As a conclusion of law, Department determined that SDCL 62-4-1 does not allow reimbursement for the van purchased by employee. Department made no findings of fact as to whether, under the circumstances, the van constituted “other suitable and proper care” as provided for in SDCL 62-4-1. The circuit court, however, made a factual determination that employee was confined to a wheelchair and therefore needed the van for transportation to obtain medical services. The circuit court noted that employer expended funds to equip the van with a lift to facilitate employee’s use of it. From these facts, the circuit court concluded, as a matter of law, that the van constituted “other suitable and proper care” under SDCL 62-4-1.
When no findings of fact are stated in an agency’s final decision, it is not within the province of the circuit court to make such findings on review. SDCL 1-26-25 specifically states that an administrative agency’s final decision “shall include findings of fact and conclusions of law, separately stated.” In State Dept. of Public Safety v. Eastman, 273 N.W.2d 159, 160 (S.D.1978), we stated:
Since a circuit court can only review a final decision and since a final decision must include findings of fact and conclusions of law, a circuit court cannot properly review a decision unless it includes findings of fact and conclusions of law.
See also Matter of Adams, 329 N.W.2d 882 (S.D.1983); Lemke v. Rabenberg’s, Inc., 89 S.D. 386, 233 N.W.2d 336 (1975).
SDCL 1-26-25 further states that “[findings of fact, if set forth in statutory language, shall be accompanied by a concise and explicit statement of the underlying facts supporting the findings.” In Lemke, supra, this court acknowledged that this provision was adopted from the Model State Administrative Procedure Act § 12 (1961). We cited a note prepared by that conference which clearly reflects the purpose of the statute and the legislative intent:
“An attempt is here made to require agency findings to go beyond a mere statement of a general conclusion in the statutory language ... or in language of similar generality. The intent is to require the degree of explicitness imposed by such decisions as Saginaw Broadcasting Company v. Federal Communications Commission (Ct.App.D.C.1938), 96 F.2d 554, where the court required a statement of the ‘basic or underlying facts.’...”
89 S.D. at 391-92, 233 N.W.2d at 339. We conclude that SDCL 1-26-25 requires Department to make a factual determination as to whether the van purchased by em*135ployee constituted “other suitable and proper care” as stated in the language of SDCL 62-4-1.
Finally, employee contends that she is entitled to attorney fees pursuant to SDCL 58-12-3. Department denied the allowance of attorney fees and the trial court affirmed the denial.
SDCL 58-12-3 provides generally that if it appears from the evidence that an insurance company has refused to pay the full amount of any loss, and if such refusal is vexatious or without reasonable cause, Department, the trial court, and the appellate court shall, if judgment or an award is rendered for employee, allow employee a reasonable sum as an attorney fee to be recovered and collected as part of the costs.
In Tracy v.T&B Construction Company, 85 S.D. 337,182 N.W.2d 320 (1970), this court ruled that whether or not an insurer’s refusal to pay is vexatious or unreasonable is necessarily determined upon the facts of each particular case. In the trial court’s memorandum decision, which was incorporated by reference into its findings of fact, the court held that under the facts of the case Department’s decision denying attorney fees was not clearly erroneous nor an abuse of discretion. The court continued stating that the insurer was exercising its right of appeal, and could not be punished for exercising a right which was conferred upon it by our legislature.
“This court presumes that a trial court’s findings of fact are correct.” North River, 296 N.W.2d at 915; Wilson v. Allstate Insurance Company, 85 S.D. 553, 186 N.W.2d 879 (1971); Hilde v. Flood, 81 S.D. 25, 130 N.W.2d 100 (1964). “We are, therefore, bound by the trial court’s decision on this matter unless the record shows that decision to be clearly erroneous. SDCL 15-6-52(a).” Ranger Insurance Company v. Macy, 88 S.D. 674, 681, 227 N.W.2d 426, 431 (1975).
Upon a review of the record and the facts of this case, we cannot say that the trial court's determination that employer’s refusal to pay employee’s claim was not vexatious or without reasonable cause was clearly erroneous. We therefore affirm that portion of the trial court’s judgment denying attorney fees under SDCL 58-12-3.
Accordingly, we affirm in part, reverse •in part, and remand to the circuit court with direction to remand to Department for the factual determination required by SDCL 1-26-25.
FOSHEIM, C.J., and MORGAN, J., concur. WOLLMAN and HENDERSON, JJ„ concur in part and dissent in part.