Let me help you with rectifying the invoices attached incorrectly, and ensure to link them to the correct account, @supplier.

When you unlinked a bank account from online banking, your existing data won't be affected. In your case, you'll want to open your register to unlink the invoice from the incorrect transaction.

Here’s how:

1. Go to the Accounting menu, then click Chart of Accounts.
2. Locate and click the View register of your bank.
3. Search the transaction, then make changes to the available fields.
4. If you want to change something in the grayed-out sections, select Edit. This opens the full transaction form where you can make additional changes.
5. When you're ready, select Save or Save and close.

Check out this article for further information on tracking down transactions in your account history so you can review or modify them in QuickBooks Online.  

I'm always around to guide you again. Please feel free to visit and post some more of your concerns.