Thanks for posting here in the QuickBooks Community and letting us help you, @Annie.

I want to make sure you're able to complete processing your refund. Let's try some browser troubleshooting for this concern. You can try logging in to your account in a private browser and test of the same error comes up there. 

Unexpected issues in QuickBooks are sometimes affected by the amount of data stored in the cache. This is because a regular browser will constantly overwrite itself and will not remove history unless done manually.

Private browsing will not save any history, so it's a great place to identify issues in the browser. Use these keyboard shortcuts to launch a new private window:

• Google Chrome: press Ctrl + Shift + N  
• Mozilla Firefox: press Ctrl + Shift + P
• Safari: press Command + Shift + N

If it works, clear the cache to resolve browser issues in QBO. Using a different browser can also help. Refer to these links to learn more about processing customer refunds in QuickBooks Online and QuickBooks Payments:

• Void or refund credit card payments in QuickBooks Online
• Record a customer refund in QuickBooks Online

If the problem still persists after trying out private or other browsers, I recommend getting in touch with our Support Team. They can help report this to our engineers who can help with program bugs and other technical concerns.

1. Go to the Help menu in QuickBooks, then choose the Search tab.
2. At the bottom click on Contact us.
   
3. Enter the keyword Account Management and Billing in the What can we help you with? box.
4. On the next screen, scroll down to How would you like to connect with us section.
5. Choose your contact options.
6. When using chat option, make sure to enable pop-up windows. The chat box will appear at the bottom right section of your monitor, and an agent will be with you shortly after. 

This thread is always open for additional questions and updates. If you need further assistance with QuickBooks refund processing, tag me anytime. I'm always right here to help.