Provided further that in the event of the Gem and Jewellery units to whom the gold or silver has been supplied, fails to export the jewellery made out of such gold or silver within the time specified in the Export and Import Policy under the respective Scheme, the nominated agencies shall deposit duty on the quantity of the gold or silver not contained in the jewellery exported at the rate of duty of customs leviable on the gold or silver, as the case may be, as provided in the Notification No. 80/97-Customs, dated the 21st October, 1997 within seven days of the expiry of the period within which the said jewellery manufactured out of the said gold or silver was supposed to be exported.