If required by the Comptroller - General of Customs a
certificate in such form and to be given by such person as may be prescribed
shall be produced in proof of the due landing according to the export entry of
any goods subject to customs control, and the Collector may refuse to allow
any other goods subject to customs control to be exported by any person who
fails within a reasonable time to produce such certificate of the landing of
any such goods previously exported by him or her or to account for such goods
to the satisfaction of the Collector.