I understand the importance of attaching the receipt to all your transactions, mrprecision.

We can only add receipts to money-out transactions (bills and expenses) in QuickBooks Online. In the meantime, you'll want to record the refund manually. Then, attach the file to the Attachments section.

Beforehand, make sure that the receipt's format is supported. Check the acceptable file types in this article: Attachments in QuickBooks Online.

Once ready, you can follow these steps to record the transaction:

1. Go to + New and then select Vendor credit.
2. Select the name of your vendor.
3. Choose Category details or Item details. 
4. Add the other necessary details to complete the transaction.
5. Scroll down to go to the Attachment section.
6. Click Save and close.

For visual reference, I've added a screenshot below.

Once done, exclude the bank transactions to avoid duplicates.

Moreover, there are several ways to add receipts to your money-out transactions. To learn more about this, I suggest browsing this article: Upload your Receipts and Bills.

Additionally, I've added this article to help you review the downloaded bank and credit card transactions and put them in the correct accounts: Categorize Online bank Data.

Please keep us posted if you need help tracking or managing vendor transactions. I'll do my best to provide you with the assistance you need. Keep safe!