No new files can be generated or uploaded through CPanel or FTP.

Whatever method I try, the only thing I can create or upload is folder.
-Whenever I create a file in the Cpanel File Manager I get the Created message but nothing in the folder.
-If I try to upload them through Cpanel Upload feature it says OK, but again nothing in the folder
-If I try it with FileZilla again nothing. For a split of a second the copied file can be seen in the target directory then it disappears.

Any idea why???