Refund of credit ledger amount

We have only IGST purchase which adjusted with our sales CGST & SGST, but every month we have also transport RCM, so excess credit ledger is such type of input.

GST law permits refund of unutilised ITC in two scenarios, namely if such credit accumulation is on account of zero rated supplies or on account of inverted duty structure, subject to certain exceptions.
Since this does not belong to any of them, the refund of such amount cannot be claimed via RFD-01