—Order, Supreme Court, Bronx County (Douglas McKeon, J.), entered November 1, 1994, which denied plaintiff’s motion for summary judgment and granted defendants’ cross motion for summary judgment dismissing the complaint, unanimously affirmed, without costs.
The IAS Court properly determined that no triable issues of fact existed as to either plaintiff’s liability for certain emergency repair liens or the validity of the repayment agreement dated January 25, 1990 and executed by its president. As no challenge to the liens was made within four months of notice thereof, here, no later than January 25, 1990, the action was untimely (see, Solnick v Whalen, 49 NY2d 224). Further, plaintiff subsequently ratified the agreement and its president’s *251authority to enter it by making payment pursuant thereto (see, Kamenitsky v Corcoran, 177 App Div 605). Plaintiff presented no evidence of fraud, misrepresentation or mistake with respect to its claim for rescission, and mere conclusions, expressions of hope, or unsubstantiated assertions are insufficient to defeat a motion for summary judgment (see, Zuckerman v City of New York, 49 NY2d 557, 562).
Plaintiffs claim of failure to follow regulations was improperly raised for the first time in reply to the motion (see, A & J Produce Corp. v De Palo Indus., 215 AD2d 317). Further, plaintiff has waived its due process claim by failing to raise it before the IAS Court (see, Martin v Manhattan & Bronx Surface Tr. Operating Auth., 198 AD2d 160). We have considered plaintiffs remaining claims and find them to be without merit. Concur—Murphy, P. J., Rubin, Ross, Williams and Andrias, JJ.