I love ebay, and unfortunately have had experiences similar to yours
One thing I've learned: Most (notice I didn't say "all") good sellers will leave you postive feedback immediately after they recieve your payment. The bad-sellers will wait to see what feedback you give them and if it's bad, will more than likely give you bad feedback just to ruin your rating.
Always, Always, Always check the feedback of a seller
before you place your bid. When I ebay, I always check out their feedback, and if there is any negative feedback, I check it out to see what the negative feedback was for. (By doing this sometimes you can catch "patterns". For example, one seller I dealt with seemed to ship her items a month or two after they were already paid for. (the negatives and neutral feedback that she had all consisted of either "never shipped item" or "finally got the item after 2 months") Since she hadn't had a negative in awhile, I bought from her, and sure enough -- I waited 2 months for my item. So if you do decide to buy from someone who has a 'history' like that, know that you may have to deal with what everyone else has and that it wasn't just an isolated case.)
I hope everything works out for you and that you at least get your money back.
P.S. DO NOT EVER UNDER ANY CIRCUMSTANCE BUY DVD's on EBAY!!! A guy came into our store the other day trying to sell us these DVD's and we couldn't buy them because they were all bootleg copies (with very convincing case covers). He said he bought them on eBay. A LOT of people make that a 'business' for themselves on eBay, and while it sucks that there are probably some genuine deals out there, I wouldn't take the chance.