How to unscrew my digital life equipment DLC 200C

I am trying to move and need to remove my Digital Life equipment.  I cancelled my account after having the alarm system for over 3 yrs for which AT&T said that it was no need to return equipment.  So I didn't give it a second thought until now I am moving out of my apartment and need to remove this equipment so I can get back all of my security deposit.  However, I can't seem to find where to find any screws or anything as to where to undo this thing from the wall.

Help me please.