Hi there, @ProSapien.
Thank you for providing detailed information here in the Community. I can help you record the refund check in QuickBooks Online.
It's recommended to track the date you receive the check, as well as the time it was deposited to the bank. You can use the Journal Entry (JE) feature to record the transaction, then put it on the Undeposited Funds account.
However, I suggest reaching out to an accountant for expert advice about which accounts to debit and credit. This way, we'll be able to ensure your books are accurate and error-free.
Here's how to enter a JE:
- Click the + New option in the upper-left corner.
- Select Journal entry under Other.
- Choose the accounts to debit and credit.

- Enter the necessary information.
- Hit Save and close.
Once you're ready to add it to your bank, you can proceed with making a deposit (the JE should reflect as a transaction you can add to your bank). The option is available when you press on the + New option from the left side (see screenshot below).

I've also attached an article you can use to learn more about debits and credits when creating journal entries in QuickBooks: Create a journal entry in QuickBooks Online.
Drop me a comment below if you have any other questions about entering transactions in QuickBooks. I'll be happy to help you some more.