Wow, it really irks me when LPS employees are idiots. Mollies are aggressive fish, which means they aren't supposed to be recommended tank mates for Betta's. However, my mollies are just attention queens and aren't aggressive at all. I guess I got lucky because they are so sweet. I am sorry you didn't have such good luck with your betta and mollies. You could get some tetras, ADFs, etc.
Males; all VT; Jello♥, Binky, Killer, Jinx, Shadow♥, Viper