Let's create a Journal entry to write off the significant overpayment for your supplier, Johann.
Before proceeding, please consult your accountant to confirm the accuracy of your records.
Here's how:
- Click the + New button and choose Journal entry.
- On the first line, select an account and enter the amount in the Debit or Credit column as needed.
- On the next line, choose the other account and enter the same amount in the opposite column.
- Verify the amounts; the Credit column on one line should match the Debit column on the other. This ensures the accounts are balanced.
- Enter information in the memo section so you know why you made the journal entry.
- Click Save and close.

I've added an article explaining how to enter a prior balance for a customer who owes you money or a supplier you need to pay: Manage outstanding balances for customers and suppliers in QuickBooks Online.
You can always get back to the Community space if there's anything else you need. We're here to help.