Call HDFC Bank customer care and request debit card blocking
Use HDFC NetBanking and block the debit card from the Cards section
Use the HDFC MobileBanking app and block the debit card
Send an SMS from your registered mobile number to the HDFC card-blocking number if available for your account
Visit the nearest HDFC Bank branch and request card blocking
If your card is lost or stolen, block it immediately and request a replacement card
Keep your account details and registered mobile number ready for verification