When i try to create and save cronjobs in my cpanel it simply clears the /var/spool/cron/username file. If i edit the file by hand and then try to modify it with cpanel it clears the file. Im not over my quota and I have no idea how to fix this.
Is the filesystem containing the crontab files over quota? That's not the same filesystem (and quota) as your home directory. You'd need to talk to your host about getting it fixed if it is over quota.