To unlock the card, log in to the ZEN app.
If you unblock the card which is added to Apple Pay or Google Pay, it is restored in both services and you can use it without any problems.
To unlock your card using the app, log in, and then go to the accounts view. By swiping up from the bottom edge of the screen, you will expand the card section view. Select the card you are interested in, then press 
. Now you can see all the details of your card. Click on "Security", then select "Unlock card".