You should read-up and look at all the different possiblities. Put a pair of clowns in there in the meantime. They are hardy and get along with most everything. I have a firefish, my tank is peaceful, the blue damsel might not be as aggressive at first, but I wouldn't risk it, pull them out. Your LFS should compensate you for what you paid as long as you use it to your next purchase there. If not, find a new LFS.
There are tons of options, I would start with easy-care, hardy, friendly fish. You don't want to waste a lot of money finding out who is not compatible, they have charts for that. Don't spend more than 30$ on a fish until you have figured it out, get a cleaner shrimp, they are fun to watch and add a new dimension to your tank.