Judge.me cannot export from eBay the reviews. I am not sure if there exists an app that does this. So the way of doing it would be by manually creating a CSV file with the right format, that contains all of your eBay reviews, that later you can import into Judge.me.
Format the file correctly, by following this guide over here:
When your file is ready, you can send it to us (email@example.com), we'd check everything is ok and proceed to import it.
How export ebay reviews into a csv file