To level the rear only, you should have gotten the Otto-Max 2" coils for the back only. The Belltech is a 2/4 kit and should be combined with shocks. Sounds like a full 2/4 kit is in store for you! Sorry they messed you up!
Edit: Here is what my full BellTech 2/4 kit looks like on my quad cab, if you want to do the full kit