"Notice of Cancellation
You may cancel this contract, without any penalty or obligation, within five (5) days from the date the contract is signed.
If you cancel any payment made by you under this contract, it will be returned within ten (10) days following receipt by the seller of your cancellation notice.
To cancel this contract, mail or deliver a signed dated copy of this cancellation notice, or any other written notice to
(name of seller) at (address of seller)
(place of business) not later than midnight (date) I hereby cancel this transaction,
(date)
(purchaser's signature) "
Okla. Stat. tit. 24, § 137