The procedure to block your Debit Card is very simple. If you want to block the Debit Card via NetBanking for an HDFC Bank Debit Card, the procedure is: Login to your NetBanking account Click on the New Debit Card Under this tab, you will find an option for Debit Card hot listing. If you click on this, you will see the different cards that are linked to your bank account Select the Debit Card that you wish to be blocked. You will need to input the reasons for hot listing. Once you do that, press confirm The system will hotlist or block your Debit Card online and send you a confirmation. Debit Cards can be blocked via Phone Banking as well. The procedure of how to block Debit Card by Phone Banking is: Call up the bank and authenticate yourself Authenticate and confirm the Debit Card details The Phone Banking customer executive may ask you for some security questions. So before you call, be prepared to answer those questions. Once confirmed, the customer executive will block your Debit Card.