Why was my cashback for my RM 200 pre-authorization transaction at petrol stations clawed back?

The GX Card cashback is rewarded upon the successful authorisation of a transaction, including pre-authorised transactions like petrol purchases. If the final purchase amount is lower than the pre-authorised amount, the excess pre-authorisation amount is released. This means that any cashback applied to the portion of the pre-authorisation that exceeds the actual purchase amount will be adjusted and reversed.