You may be trying to use an old card after a replacement was sent.
The Santander app lets you unblock a card instantly in most cases. how do i unblock my santander debit card
If your card was blocked because you entered the wrong PIN too many times, you cannot simply "unfreeze" it in the app. You will need to "Unlock" the PIN at an ATM. Visit any (or most Link ATMs). Insert your card and enter your correct PIN . Select 'PIN Services' or 'Other Services' . Choose the option to 'Unlock PIN' . You may be trying to use an old