If the tax imposed by title nine of the federal Social Security Act or any other federal tax against which contributions under this title may be credited, shall become inoperative, the provisions of this title shall become inoperative. Any unobligated fund in the state unemployment compensation fund or returned by the United States Treasurer, because the federal Social Security Act is inoperative, shall be refunded to the contributors pro rata to their unexpended contributions.
SDCL 61-1-55