If you believe there is something wrong with your card, like a transaction that you do not recognise, we recommend that you freeze your card immediately through the app. Open the app, go to "Cards" > "Freeze" and confirm the freeze.
If you confirm that there is something wrong, you should cancel your card immediately, and to do so open the app and go to "Cards" > "Settings" > "Cancel and issue another card". You can also report what went wrong with your card, and to do so open the app and go to "Cards" > "Settings" > "Report", selected the appropriate option and confirm to report. Done, your old card will not work any longer and you will have a new card in the app.