Frank Riccardi (defendant) purchased a Model A-660 Acousticon hearing aid from Frank Bartus (plaintiff), a licensed representative of Acousticon, making a down payment of $80. When the hearing aid was delivered, however, it was a Model A-665, which was represented to be a newer, improved version of the A-660. Riccardi was fitted with the aid, but it immediately bothered him. Approximately one week after receiving it, he returned the hearing aid to Bartus, complaining about headaches it caused and that it was not the model he ordered. Bartus offered to obtain an A-660, to which Riccardi did not respond affirmatively or negatively. Neither party expressed anything about canceling their existing contract. Bartus immediately contacted Acousticon, which promptly sent a letter to Riccardi offering to deliver the A-660 or a replacement of the A-665 he had been given. Riccardi declined to accept either, and Bartus then sued him for the balance owed on their contract. The trial court considered the principal legal issue of the case.