(a) A written or oral promise of a retail seller to compensate a retail buyer for referring customers or prospective customers to the seller or for referring the seller to customers or prospective customers must be disclosed in a retail installment contract if the promise is:
(1) part of the contract;
(2) made to induce the buyer to become a party to the contract; or
(3) made incidental to negotiations between the seller and the buyer with respect to the sale of the goods or services that are the subject of the contract.
(b) A contract that contains a provision required by Subsection (a) must provide that the amount owed under the contract at any time is reduced by the amount of compensation owed under the promise.