IGST REFUND from Custom Pending

Amit Puranik (Pvt ) (10 Points)

22 December 2018  
Hello

Our IGST refund from Custom of FY 17-18 is pending due to mismatch of invoice number on shipping bill and invoice number in GSTR-1. e.g inv no on SB is 001 and inv no in GSTR-1 is 1.
How can we get this refund back?