Hey there, @ed4becky! Thanks for contacting us. I’m happy to help you.
To confirm, when you disabled all plugins, did you also switched to a default theme such as Storefront to check if the issue persisted?
Can you please share a screenshot of what you see when you click the first refund button so we can take a look?
I recommend using https://snipboard.io. You can share the direct link to the image as a response to this topic.
Please make sure to remove sensitive information from it.
Furthermore, I’d like to understand your site properly. Please share with us the necessary information below for us to investigate the issue further:
System Status Report which you can find via WooCommerce > Status > Get system report > Copy for support.
Fatal error logs (if any) under WooCommerce > Status > Logs. Then you can use the selector to search for Fatal Errors.
You could copy and paste your reply here or paste it via https://gist.github.com/ and send the link here.
Have a wonderful day!