If the petition for refund allowed by Section 40-12-23 is approved, in whole or in part, the department shall certify the amount which it approves to be refunded by the state and county. The state Comptroller shall draw a warrant payable to the applicant for the amount of the refund to be made by the state, and the county commission of the county in which such payment was made shall draw a warrant upon the county treasurer or county treasury payable to the applicant for the amount to be refunded by such county. Claims for refund hereunder shall not be subject to assignment, except assignments resulting by operation of law.