Upon the written request of the original purchaser thereof and upon the return of any unused stamps, the Tax Commissioner shall redeem such stamps. The Tax Commissioner shall prepare a voucher showing the amount of such returned unused stamps and shall cause to be drawn a warrant upon the State Treasurer for such amount in favor of the person returning such unused stamps. The refunds shall be paid from the various funds named in section 77-2602 in the same proportions as the proceeds of the tax are allocated. By the terms of sections 77-2601 to 77-2615, the Tax Commissioner and the State Treasurer are specifically authorized to adjust all errors in payments for unused stamps.