Cal. Financial Code § 18635

Whenever the interest or charges, or interest and charges deducted in advance exceed the maximum provided by this division, by reason of subsequent repayment of the loan, a new loan, refinancing, or otherwise, or any portion thereof prior to maturity, such excess shall be rebated to the borrower or credited on any balance owing by the borrower to the company. The rebate shall be the difference between the total of the precomputed charge, any charge for extending the first due date, plus any default or deferment charges and the charges at the contract rate computed on unpaid principal balances for the number of days actually elapsed by applying each payment first to charges and the remainder to principal. The tender, by the borrower or at his request, of an amount equal to the unpaid balance less the required rebate must be accepted by the company in full payment of the loan contract.