At no time prior to the satisfaction of all liabilities with respect to officers and
employees participating under the provisions of this Act, 1924 Ga. Laws, page 167,
as amended, and their beneficiaries shall any part of the corpus or income of the
fund established under this Act be used for, or diverted to, purposes other than for
the exclusive benefit of such officers, employees and beneficiaries, except that a
contribution by an employer to the fund established under this Act made under a mistake
of fact may be returned to such employer within one year after the payment of the
contribution.