P entered into an Installment Sale Contract and Security Agreement with Cherry Creek Development, Inc. (Cherry) to purchase a mobile home in March 2010. The purchase price was $47,500. Cherry retained a security interest in the mobile home. P paid $3,800 down and agreed to pay $483 per month for fifteen years to pay off the remaining $43,700 balance, with payments due on the 19th of each month. A late fee would be charged for any payment that was five days past the due date. Cherry assigned the Contract to its parent company, D. On December 10, 2015, P vacated the mobile home and allowed D to take possession. P signed a Full Release of Contract and relinquished all rights to the mobile home. The release stated that P was fully aware that by signing this 'I am completely removing my rights to all aspects of the home and I will not be entitled to any rights of this home or refund of all money applied to the home including but not limited to the down payment, and all payments made on the home and the lot up to this day.' P owed $34,499.01 under the Contract. D resold it without notice to P, for $45,500. P requested an accounting which D did not provide and D did not refund any surplus. P sued D for failing to provide for an accounting of the results of the resale of the mobile home pursuant to § 30-9A-616(2)(a)(ii), MCA; for failing to pay her the surplus proceeds of the mobile home's resale pursuant to § 30-9A-615(4)(a), MCA; and alleging that the trial court should apply all her payments to the principal, providing for a larger surplus, because D failed to comply with the Retail Installment Sales Act (RISA), Title 31, chapter 1, part 2, MCA. D moved for summary judgment arguing that the Release terminated the contract and or that P was equitably estopped because she made false representations that she would not pursue her rights under the UCC when she signed the Release. The court granted the motion and P appealed.