What do GST rules say about refund for exporting goods and their payment

TNC Rajagopalan explains GST rules on exports and scrips.

We have exported goods on payment of IGST and got refund of the same also under Rule 96 of the CGST Rules, 2017. We also have some cases where we exported goods under LUT without IGST payment and claimed refund of unutilised input tax credit under Rule 89 of the CGST Rules, 2017. Now, in some cases, we agreed to short payment from buyer due to quality claims. We sought write-off from our bankers for the shortfall. They have asked us to surrender proportionate export incentives. We have surrendered the proportionate drawback and MEIS benefits. Are we required to surrender