x10hosting now deletes files 10 MiB (or larger) in size - that have been on the server (in any folder) for more than about 4 hours - from non-upgraded free-hosting accounts only
the 4 hours time limit allows users to upload and extract site backups - and is not for short term file hosting...
you can store the files at a file-hosting service (which x10hosting free-hosting is not) then link to them from your Web page