S.C. Code Ann. § 37-2-502 – Buyer's right to cancel

(1) Except as provided in subsection (5), in addition to any right otherwise to revoke an offer, the buyer may cancel a home solicitation sale until midnight of the third business day after the day on which the buyer signs an agreement or offer to purchase which complies with this part.
(2) Cancellation occurs when the buyer gives written notice of cancellation to the seller at the address stated in the agreement or offer to purchase.
(3) Notice of cancellation, if given by mail, is given when it is properly addressed with postage prepaid and deposited in a mailbox.
(4) Notice of cancellation given by the buyer need not take a particular form and is sufficient if it indicates by any form of written expression the intention of the buyer not to be bound by the home solicitation sale.
(5) The buyer may not cancel a home solicitation sale if, by a separate dated and signed statement that is not as to its material provisions a printed form and describes an emergency requiring immediate remedy, the buyer requests the seller to provide goods or services without delay in order to safeguard the health, safety, or welfare of natural persons or to prevent damage to property the buyer owns or for which he is responsible, and
1. (a) the seller in good faith makes a substantial beginning of performance of the contract before the buyer gives notice of cancellation, and
2. (b) in the case of goods, they cannot be returned to the seller in substantially as good condition as when received by the buyer.