GST refund

There are some conditions laid down for successful claiming of refund of IGST paid on exports:

GSTR-3B for the month is filedTable 6A of GSTR-1 has been filedDetails of Shipping Bill and Invoice provided in Table 6A of GSTR-1 should matchThe IGST amount mentioned in GSTR-3B is equal or more than the IGST mentioned in Table 6A of GSTR-1.

thus it is mandatory to file GSTR 1 too claim refund..