Transactions may not be voided after an acquirer has sent the transaction to settlement. Acquirer’s rules and schedules on what can or cannot be voided vary. If you are unable to void a transaction will need to refund it, see below for more details.
There are 2 ways to void a transaction.
1. To void a transaction go to the Billing tab and select the payments button. Then select the payment you wish to void and click edit.
2. In the edit payment window the Process APX Payment button will now show as Void Payment.
Please note: A receipt is sent to the client after the transaction is voided
Also Deleting an AXP payment in OfficeTools will also void the transaction