How big was the purchase?

Your best bet, before you try outside legal things, might be to contact ebay chat. I was going to say ring but apparently there is only online chat available at the moment.

Have your facts ready in order, be polite, keep to the key points and they may at least reimburse you, you never know till you try. 

From what i have read from others, emails rarely work, you would most likely just get a stock answer.