"552 Disk full" - or "522 Disk full" - or "please upload later" - or "server is running out of disk space" - or "error 28 from storage engine" - or errors like that - are at the server level, indicating that the shared data storage partition(s) are full or nearly full or a server read/write-file type of error - which is preventing you from uploading files - or using cPanel - or your site from using a MySQL database - or your script from starting a session - this is a server issue so Admins will need to fix it - your files (data and disk space used) are NOT the problem and there is nothing you can do but wait