Refund mechanism for merged GSTINs allows filing under 'Any other' from new GSTIN with specified debit procedure. Affected taxpayers may file refund claims from their new GSTIN under the 'Any other' category, stating in Remarks the actual refund category and attaching required supporting documents; initial filing need not debit the electronic credit ledger. The proper officer will calculate admissible refund, verify completeness and eligibility, request a written debit from the electronic credit ledger if payable, and upon proof of debit issue refund and payment orders. Refunds requiring ledger debit or re-credit shall not be filed using the old GSTIN.