You can suspend your card if you want to prevent any transactions on your card.
Tap on your on-screen card > go to settings (top right corner) > tap on suspend card > select a reason to suspend your card from the drop-down menu > confirm the suspension
Verify your identity by entering your date of birth and your card will be suspended.
Note: slice visa card is available only to Card Members and can be activated again by simply logging in with your details.