Bought Vista on Ebay and won't activate

I asked in a question earlier if there was a way to contact MS about the
number of activations on a key for vista. The reason I was asking is that a
person on ebay sold me and open copy of vista ultimate. In the auction, it
said the product had been opened but never activated. Then he used my money
(in part) to buy a solid state laptop hard drive. That really pissed me
off, so I was going to see if I could get proof of an earlier activation on
the poduct he sold me. That way, I could file a claim as an item
signifigantly not as described for this copy of vista. I know I shouldn't
have bought an open box, but that is what you get for being me I guess.