In addition to any other right to revoke an offer, a buyer shall have the right to cancel a home solicitation sale until midnight of the third business day after the day on which he has signed an agreement or offer to purchase. Cancellation shall become effective when the buyer gives written notice of his intention to cancel to the seller at the address stated in the agreement or offer to purchase. Notice of such cancellation, if given by mail, is given when it is deposited in a mailbox properly addressed and postage prepaid. Such notice of cancellation given by the buyer need not take any particular form and shall be sufficient if it indicates by any form of written expression the intention of the buyer not to be bound by the home solicitation sale. Notwithstanding any above-mentioned provision, a buyer may not cancel a home solicitation sale where he has requested and the seller has provided goods or services without delay because of a bona fide emergency and either the seller has in good faith made a substantial beginning of performance of the agreement before the buyer has given notice of cancellation, or in the case of goods, such goods cannot be returned to the seller in substantially as good condition as when they were received by the buyer.