Hi there, brian.
You can use Refund Receipt to record the reimbursement via cash or check for goods or services.
Follow the simple steps below:
If this is an inventory item, the quantity on hand will automatically adjust to what you have in stock after you issued a refund receipt.
For additional reference, you can check this article to learn how to refund a customer in QBO: Record a customer refund.
I'm still here to help you more if you have additional questions for me. Have a good one!