Rule 96B and write off of outstanding export dues

We did not recover 90% of Export dues and Bank has since written off the entire outstanding based on our application and refund of DBK plus CA certificate.  However, GST Dept cites rules 96B and demands RBI approval..Else denial of zero duty export. But FEMA gives this right to Bank dealing export docs. What Bank does with RBI, it is their internal matter. Please advise to avoid SCN.