You should be able to use EITHER apt-get or cron-apt in batch mode, with "cron".
Please read this article - it might help with some of the problems you've been having:
Then please try again. If you encounter problems, or have questions, then please open a new post. Always, please try to be as specific as possible:
1. Exactly what steps did you try?
2. Exactly what went wrong (cut/paste error messages, if possible)
'Hope that helps .. PSM