Don't waste your time on the Better Business Bureau - they are a scam with PR better than DeBeers's. Just follow the money - all BBB's are funded 100% by member merchants, if you file a complaint against a current member, the BBB will do all it can to make sure the complaint ends up in the circular file in 6 months or less - one or two of those steps involve a half-hearted attempt to fix things, but most of it is just procedural jerking you around. If the merchant is not a member of the BBB, they will probably use your complaint as extortion to get the merchant to join, as in "if you don't join, then this complaint will become public record, but if you do join, we'll squash it like we do for all the other members."

Ebay I don't know so well wrt to car dealers, but in general ebay sides with sellers and not buyers because it is the sellers who pay ebay.