Del. Code tit. 6 § 4312
No right of action or defense arising out of a retail installment sale which the buyer has against the seller, and which would be cut off by assignment, shall be cut off by assignment of the contract to any third party whether or not the third party acquires the contract in good faith and for value unless the assignee given notice of the assignment to the buyer as provided in this section and within 15 days of the mailing of such notice receives no written notice of the facts giving rise to the claim or defense of the buyer, or unless the assignee acquires the contract or evidence of indebtedness relying in good faith upon a certificate of completion or certificate of satisfaction signed by the buyer. A notice of assignment shall be in writing addressed to the buyer at the address shown on the contract and shall identify the contract and state that the buyer must, within 15 days of the date of mailing of such notice, notify the assignee in writing of any facts giving rise to a claim or defense which the buyer may have. The notice of assignment shall state the name of the seller and buyer, a description of the goods and services, the time balance and the number and amounts of the installments. If a certificate of completion or satisfaction is relied upon, the following notation must appear at the top thereof in at least 10 point bold type: "Notice to Buyer -- Do Not Sign this certificate until all services have been satisfactorily performed and materials supplied or goods received and found satisfactory."
6 Del. C. § 4312