Maryland Code, Commercial Law § 12-615

(a)(1) If, in addition to any down payment, a buyer is required under an installment sale agreement to make a payment to a seller before the seller is obligated to deliver the goods sold, the buyer may cancel the installment sale agreement before delivery or tender of the goods by the seller.

(2) Notwithstanding any provision of the installment sale agreement, if it is canceled pursuant to this subsection, the seller shall refund to the buyer within ten days after notice of the cancellation an amount equal to at least 90 percent of all payments made by the buyer under the installment sale agreement, including any down payment.