One gripe doesn't equate trying to ruin trade by telling people not to buy anything at all. I'm sorry to hear that the dress wasn't suitable, but for all the owner knows, it could've been worn for the occasion intended, and then sent back with a phoney excuse for a refund.
I'm sure that because sizes can vary so greatly, that had your friend contacted the place and asked for an exchange, the company would've obliged. I've sent a few things back which I've bought via the internet, and there were no problems at all. This particular store has some fabulous gowns, and boasts good customer services, so I can't understand what's gone wrong. x