Gstr - 3b amendment

Dear Sir / Madam,
We have a export Sale in August 2017, and we have filed GSTR-1 export in  6A, but while filling GSTR-3B, we wrongly filled all amount in Regular supply, and in Zero rated supply we filled 0.00. when we submitting for refund there is error appearing that in GSTR-3B Zero Rated supply and in GSTR-1 6A should be match.

what should we do in this case for export refund.