You may use one of the following options to block your Debit Card.
(1) You can instantly block your debit card using Mobile Banking App (Nexa),
(2) Block your debit card in Netbanking.
(3) By sending sms keyword BLOCK to 9223009999 from your registered mobile number to block all cards linked to the mobile number. To block a specific card send BLOCK<space><last 4 digits of card> (e.g. BLOCK 4567) to 9223009999 from your registered mobile number.
(4) Give a missed call to 9223009999 from your registered mobile number. In the subsequent IVR call received from the bank, select 3 to block your debit card.