Matching of input tax credit triggers reversal and interest liability until supplier amends return and recipient adjusts liability. Matching requires reconciling a recipient's inward supplies with the supplier's outward returns and import IGST; matched claims are accepted and communicated. Discrepancies or duplications are communicated, and unrectified discrepancies or duplicative credits are added to the recipient's output tax liability and attract interest from the date of availing the credit. If the supplier later declares the invoice within the prescribed period, the recipient may reduce the added liability and receive interest refund to the electronic cash ledger, capped by interest paid by the supplier.