Ebay is VERY big on this sort of stuff. Keep the listing number in your "Bought items" and follow through the 14 pages or so Ebay will make you go through to file a formal complaint. Then Ebay will take over. If they do a lot of business on Ebay, they will take care of you to avoid what Ebay can and WILL do (Seen it done first hand on a handloader I bought a few years ago). Else it's going to be small claims court in the jurisdiction where you bought it from.
If it was messed up, why'd you try and fix it and not start all this then? You MIGHT have done yourself in a lil there, G.
I said it before, I'll say it again, 70% of what you find on Ebay or Craigs list is either a scam or a rip-off. There are deals to be had from honest people, but be smart about it! (I've been ripped a time or two, but normally make out OK, eh Jeremy?).
Ray