Drawback under gst transitional period

Dear Experts,

We have exported 'Tea' under LUT without paying IGST and claimed dawback 1% .

Now at the time of refund IGST and CGST claim is disallowed on the ground of claiming Drawback at higher rate .But as per our C& F Agent there was no option of claiming at lower or higher rate at the time of submission the documents at Custom Site in the month of July. (A is printed against the HSN code in Shipping Bill)

Is there any way to get the refund. Can the IGST and CSGT amount be adjusted with our liabilty if not refunded.

Please clarify.

Thanks in advance.