Let's work together to get this sorted out, jdoran.
If you haven't make a payment in QBO but shows zero on the customer's balance, it could be that there is a Credit Memo transaction that was created. Also, the Automatically apply credits feature is enabled. Let's check if this is the case.
To check if auto-apply credits:
- Go to the Settings icon and select Account and Settings.
- Click on the Advanced tab.
- Scroll down to the Automation section.
- Toggle Automatically apply credits.
- Click on Save then Done.
You may also want to check on the invoice and verify the amount. Once verified, you need to let QBO know that the invoice was paid. For the detailed steps, please check it here.
Tag me in the comment below if you have follow up questions regarding invoices in QBO.