Step 1: Select the card you wish to block
Step 2: Tap the three dots at the top right
Step 3: Tap "Block Card"
If you have not completed a one-time Singpass MyInfo identity verification on the SimplyGo app, you will need to do so at this stage. If you have, please skip to Step 7.
Step 4: Tap "Continue" to verify your identity 
Step 5: Follow the prompts to verify your identity
Step 6: Tap "Confirm" to proceed
Step 7: Select the option you wish to refund the remaining balance to
Step 8: If you opted for the remaining balance to be refunded to a card, please select your card for the refund
Step 9: Tap "Confirm" to proceed
Step 10: Tap "Proceed"
And you're done!