CONSTITUTIONAL VALIDITY OF RULE 96(10) OF CGST RULE, 2017 - Goods and Services Tax - GST

My client imports some goods under an advance authorization scheme for job work purposes. After compilation of job work, export and clear the goods with payment of GST option. And also got the refund of IGST after filing the GSTR-3B . Now my client got the notice from customs and directed the GST department to collect the GST with interest which was sanctioned earlier as this is not legal due to Rule 96(10) of CGST Act-2017 . My client is in opinion that The effect of Rule 96(10) is an indirect violation of Section 16 of the IGST Act which provides for zero rated supply. We have claimed refund of duty after payment of duty while clearing the goods so the Government has not received any revenue. Alternatively, the we could have cleared the goods under L.U.T. route, then also it was not required to pay any duty for the same. There is no loss revenue to the government in both the cases.