Drag down the "Balances" section to reveal the full card.
You will then see three buttons underneath the image of your Mastercard: "Freeze", "PIN" and "Wallet".
Select "Freeze"
You will then see your Glint Card appear to frost over, and you will now only see two buttons. A Defrost and Cancel button.
Please note that if you accidentally cancel your Glint Card using the Cancel button, it cannot be reactivated. There is a confirmation window before you can officially cancel your Mastercard to help avoid accidental cancellations.