My friend's ebay account got hijacked and he didn't even know it until he started getting disgruntled emails from people who claimed that they had been defrauded by him. Now I always check to make sure that a seller's account hasn't been dormant for a while, because those are ones they target. I'm not saying this is what happened with your seller, but it's something to keep in mind when shopping. 100% positive feedback doesn't mean anything if someone has taken over the original owner's account.
Another thing... unless the seller has already give you positive feedback, I would caution against leaving negative or neutral feedback for them. You put yourself at a very real risk getting retaliatory negative feedback in return. I know it's against the spirit of ebay not to warn others, but someone who is not honest in an auction is not going to have any qualms about making false statements about you. (Sadly, I know this from experience.) In a way, not leaving any feedback is a statement in itself.
I'm sounding very negative here, but I really do
ebay. You just have to be a little careful.