My WebSite and All my files are Gone

Dear Support....
All pages on my sites show the standard 404 Not Found error page. I can't see any of my files in the CPanel file browser. 

CP USERNAME: RADIONOS

Quote:Not Found
The requested URL / was not found on this server.
Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.

Thanks!!!!!!!