(a) Insurers must refund the appropriate portion of any unearned premium to the policyholder not later than the 15th business day after the effective date of cancellation or termination of a personal automobile or residential property insurance policy, as required by Insurance Code §558.002(d).(b) For purposes of this section and Insurance Code §558.002(d), the "effective date of cancellation or termination" means the date the insurer receives notice of the cancellation or termination, or the date of the cancellation or termination, whichever is later. This does not change the actual date of cancellation or termination for calculating the amount of unearned premium or any other purpose.(c) Insurers may refund unearned premium by applying it as a credit to other premium due on the same policy, unless the policyholder requests otherwise.(d) This section applies to any unearned premium, including any that results from cancellation or termination of an entire policy or an endorsement.