Defo, ring and ask them to take it back.
I did initially have juvenile angels in my 12g tank - as soon as i got a bigger tank they moved out.
I now have most of my angels in a juwel vision 260 (theres six in there, 2 juveniles and two adult pairs, one of which are the parents of the little 'uns), the others, four babies are in my 3ft tank, they also will move to the 260 as for adult angels this is the only one really deep enough.
Asides from not really being fair to the fish to try and keep them in a small tank, you arent doing yourself any favours either as they wont grow, they wont display their true characters and they wont live very long.
All in all no one gets much good out of the scenario really.
Your tank would probably be better suited to some small tetras (there are lots of these, some FAR more interesting than the common neon - i like X Ray tetras, very pretty), some bamboo/wood shrimp - these are filter shrimp who cannot harm fish, or some small algae eating shrimp such as Red Cherry Shrimp, Amano Shrimp etc, and perhaps some Otocinclus cats or some small corydoras cats.
