R.I. Gen. Laws § 6-28-3: Right to cancel — Method.

In addition to any right otherwise to revoke an offer, the buyer may cancel a door-to-door sale or lease of merchandise by posting written notice of cancellation to the seller at the address specified for notice of cancellation provided by the seller not later than midnight three (3) days following the buyer’s signing the agreement, excluding Sunday and any holiday on which regular mail deliveries are not made. The notice of cancellation shall be sent by registered or certified mail. Notice of cancellation given by the buyer shall be effective if it indicates the intention on the part of the buyer not to be bound by the door-to-door sale or lease of merchandise.