Back to class! Good luck with your English in 2017.
call back (or phone back)
Definition: to contact someone by telephone who has previously contacted you by phone
(This verb has more than one meaning)
E.g.1. Sorry! Can I phone you back? My dinner’s burning! E.g.2. This is a message for John. Could you phone me back as soon as you get this message? It’s urgent.
This phrasal verb can be separated.