Cal. CIV § 1812.57

(a) Every contract for dance studio lessons and other services shall contain a clause providing that if, by reason of death or disability, the person agreeing to receive lessons and other services is unable to receive all lessons and other services for which he or she has contracted, the person and his or her estate shall be relieved from the obligation of making payment for lessons and other services other than those received prior to death or the onset of disability, and that if the buyer has prepaid any sum for lessons and other services so much of that sum as is allocable to lessons and other services he or she has not taken shall be promptly refunded to the buyer or his or her representative.

(b) Notwithstanding the provisions of any contract to the contrary, whenever the contract price is payable in installments and the buyer is relieved from making further payments or entitled to a refund under this section, the buyer shall be entitled to receive a refund or refund credit of so much of the cash price as is allocable to the lessons or other services not actually received by the buyer. The refund of the finance charge shall be computed according to the “sum of the balances method,” also known as the “Rule of 78”.