Well since this isn't a huge outfit who has lots of other properties, I don't see how you can use the dissatisfied customer angle for leverage to get something out of them.

Nothing really you can do, they are giving your money back and I am sure the fine print covers them in situations like this.

Oh, and don't think for one fucking second I believe a word of their story. I am more inclined to believe that if it was the deal you say, someone fucked up with the price and they made this shit up to cover for it.