Whether the charge is pending or completed (posted) is among the most important factors that decides if and how you can block a credit card transaction. When a credit card is used for a transaction, the bank first issues an ‘authorisation.’ This creates a pending transaction, a temporary hold that reserves the funds but does not immediately transfer them. At this stage, issuers generally cannot stop the payment themselves because they have already guaranteed the funds to the merchant. To block a pending charge, your best course of action is to contact the merchant immediately to ‘void’ the transaction before they settle their daily records.
Once a transaction is completed, it appears on your official statement and the funds have moved to the merchant's bank. At this point, you cannot technically block or stop the payment. Instead, you must initiate a reversal through a refund or a formal dispute with your bank. RBI has mandated a faster dispute resolution process, requiring banks to acknowledge complaints within 24 hours. While you can ask your bank to ‘lock’ your card to prevent future unauthorised activity, reversing a completed charge requires providing evidence of a billing error, service failure, or fraud to your issuer.