We respectfully *989dissent. In our view, Supreme Court erred in denying the motion of defendant U-Haul International, Inc. (U-Haul) seeking dismissal of the complaint against it based on lack of personal jurisdiction (see CPLR 3211 [a] [8]). Once U-Haul raised the challenge to personal jurisdiction, plaintiffs had the burden of proving that U-Haul, a foreign corporation not authorized to do business in New York, was properly served with process in compliance with Business Corporation Law § 307 (see Janko Pool Serv. v Berelson, 145 AD2d 897, 898-899 [1988]; see also De Zego v Donald F. Bruhn, M.D., P.C., 67 NY2d 875, 877 [1986]; Beris v Miller, 128 AD2d 822 [1987], lv denied 70 NY2d 610 [1987]). Plaintiffs failed to meet that burden. They failed to file, inter aha, the affidavit of compliance required by section 307 (c) (2), and that failure to adhere to “the strict requirements of [the statute] divested Supreme Court of jurisdiction over [U-Haul]” (Flannery v General Motors Corp., 86 NY2d 771, 773 [1995]; see Flick v Stewart-Warner Corp., 76 NY2d 50, 57 [1990], rearg denied 76 NY2d 846 [1990]; cf. Sorrento v Rice Barton Corp., 286 AD2d 873 [2001]). We disagree with the conclusion of the majority that plaintiffs complied with the statute following service of U-Haul’s motion papers by filing a purported affidavit of compliance. Plaintiffs attached thereto a copy of the letter of their attorney accompanying the process mailed to U-Haul, date-stamped as received. The statute, however, requires the filing of “either the return receipt signed by such foreign corporation or other official proof of delivery” with the affidavit of compliance (Business Corporation Law § 307 [c] [2]). As U-Haul correctly contends, that requirement is not met by the filing of the date-stamped cover letter, which is not “official” proof of delivery inasmuch as it was not issued by the Postal Service. “When the requirements for service of process have not been met, it is irrelevant that [the] defendant may have actually received the documents” (Raschel v Rish, 69 NY2d 694, 697 [1986]; see Macchia v Russo, 67 NY2d 592, 595 [1986]). Present—Pigott, Jr., P.J., Green, Hurlbutt, Gorski and Lawton, JJ.