Massachusetts General Laws Part I. Administration of the Government (Ch. 1-182) Ch. 167B, § 15

If it is the policy of a person to give cash refunds for payments made by cash, such person shall also give credit or cash refunds for payments made by electronic fund transfers, unless it is clearly and conspicuously disclosed at the time the transaction is consummated that such person does not give credit or cash refunds for payments made by electronic fund transfers.