If your voucher redemption was unsuccessful due to reasons like failed payment, cancelled order etc. - Don't worry! Your voucher should still be usable.
For example:
Kindly give a cool-off period of 20 minutes before re-using it. Then, repeat the order and you should be able to make use of the voucher again.
If you need further assistance, A+ Rewards are happy to look into this further for you. Please submit a ticket to us by following the steps in this article:
https://support.tngdigital.com.my/hc/en-my/articles/4407437809561-I-have-submitted-support-ticket-for-A-Rewards-how-do-i-track-it