You might have previously backed up your files, reinstalled Degoo, and now your files don't appear in the "My files" screen.
This happens because Degoo keeps track of your device through settings saved on your phone. Those settings are deleted when your phone is reformatted or if Degoo is uninstalled. Reinstalling Degoo will link your phone twice to your account but you can still download your files provided you have been active in the last 60 days.
Go to the My files screen and you will find your phone listed twice. One will say Backed up and the other You.
Your files should be in the device labeled Backed up. Download instructions are available in this article.
If you can't get to the device list, just tap the back button at the upper left portion of the screen.