There's no direct way of uploading your suppliers' refund, Maffett. Allow me to provide further details about this below.
In QuickBooks Online (QBO), you have the option to upload or import some data, so you don't have to enter it manually. However, uploading suppliers' refund or credit receipts.
In the meantime, you'll want to go to the QuickBooks App Center website to search for a third-party application that lets you import supplier refunds into the program. You can also use customer reviews to help you decide which app is best suited for your business type and needs.
Otherwise, you'll have to manually record your supplier refunds and credits into the program.
Additionally, you'll want to check out this article for the detailed steps in case you need to review all your supplier transactions in QBO: How to view and edit supplier transactions in QuickBooks Online.
Please know that you're always welcome to post a reply in this thread if you have any other questions about handling supplier refunds. It's always my pleasure to help you out again.