I can add some information about canceling customer payments in QuickBooks Online.
At this time, the option to let your clients revoke their invoice payments is currently unavailable in QuickBooks Online. This is, however, a great idea to add in QuickBooks so I'd encourage you to send your product preference to our developers. Let me show you how to send a request:
Click the Gear icon.
Enter your feedback and suggestions.
Select Feedback for the Category.
Click Send message.
If this is a credit card payment from your client, what you can do is to void the payment the same day you process the refund. Please be reminded that 3 PM PST is the settlement cut off time and anything after that is then considered next business day. Here's how to do that: