eBay's policy is consistent and written in a manner to accomodate varying state laws. The OP made a bid for a car with no reserve. The dealer refused to honor the bid and is in conflict with eBay rules on reneging because they feel the winning bid is too low in a no-reserve auction.
If this right then I say if you can't get the local (Houston) TV consumer advocate to feature your story then take your evidence (screen shot?) that it was a no-reserve auction, a copy of the eBay seller agreement rules for no-reserve auctions, and the price for a similar car from another dealer and sue for the difference in price for the cars plus legal fees.
Better yet, save yourself the hassle. Take your documentation to small claims court which has a $10,000 limit in Texas. This should cover the delta in cost between your bid and a similar car from another dealer and you won't have to worry about big legal fees if you lose.