Notwithstanding any other provision of law, in any case where an employee amount (as hereinafter defined) was paid from a State unemployment fund to the Unemployment Trust Fund, an aggregate amount equal thereto shall be paid from the Unemployment Trust Fund, as refunds, to employees who paid into the State fund the contributions upon which such payment into the Unemployment Trust Fund was based, except that in case any such employee is deceased, payment shall be made to his estate; and the payment so made in the case of any employee shall be in proportion to the contributions paid by such employee into the State fund: Provided, That payment in any such case shall be made only if application therefor is made to the Railroad Retirement Board within two years after August 2, 1946.