Hi shariglickmansg3brandingltd,

Making sure you're able to receive payments from your clients quickly is what our payments add on is all about. I can help explain more about how payments works in QuickBooks Online.

In QuickBooks Online you can receive payments from Visa, Discover or MasterCard, However American Express isn't available at this time. Since your client already sent the payment, you'll need to cancel it so it can be sent again using an accepted payment method. You can void the payment by following these steps:

1. Click Sales in the left navigation menu.
2. Go to the All Sales tab.
3. Find and select the payment transaction your to cancel.
4. Click More, then select Void.
5. Hit Yes, then OK.

Hope this was able to help.