Problem: Buyer needs a number of computers for himself and his family. Buyer agrees to purchase five desktop computers with definite specifications from Seller for a total price of $5,000. Under the agreement, the computers will be delivered at specific intervals and Buyer will pay a specified portion of the contract price at the time of each delivery. Buyer claims that the computers delivered on the first installment did not meet contract specifications, refuses to accept the shipment and cancels the entire contract. Seller sues for breach of contract. In this breach of contract action, Buyer's best defense would be that: