Let me guess. You using Maybank debit card?

If yes;

1. Call Maybank hotline
2. Tell them to activate your online transaction purchase
3. Link your debit card again in grab app
4. Grab app will detect you have pending RM 5 and it will automatically charge that instead of the normal RM 1 (refundable)
5. Continue on with your life

Probably the same steps for other banks

Hope this helps