Thank you for sharing detailed information, @G-IWI.

I'm happy to know that you're able to clear off your A/R balance by receiving the customer's payments. And I'm also here to help resolve your other issue (clear off the A/P balance) to ease your frustration.

The most common cause of a balance in accounts payable is unapplied bill payments. To clear this off, let's find the unapplied payments by running the Vendor Balance Detail report. Here's how:

1. Sign in to your QuickBooks Online (QBO) account.
2. Click Reports from the left menu.
3. Search for Vendor Balance Detail report.
4. Review the report to identify any unapplied payments.

After identifying them, you can apply the unapplied payments in Accounts Payable (A/P). Let me guide you how.

1. Click Expenses from the left menu.
2. On the page, click the Filter drop-down and select Recently paid in the Type drop-down.
3. Click Apply.
4. Select the unapplied bill payment from the list to open the Bill Payment window.
5. From the Add to Bill Payment panel, select Add for the bills to apply the payment to.
6. Click Save and close.

I'm adding this article for more guidance: Resolve accounts receivable or accounts payable balances on a cash basis balance sheet in QuickBooks.... This will also give you another option on how to clear of A/P balance.

You may also need to run other reports to review your transactions. You can check out this article: Run reports in QuickBooks Online.

Let me know if the steps above clear off your A/P balance. I want to make sure this issue is taken care of, @G-IWI.