Did you find the "car" on eBay Auctions?
If you bought it through another site and were told eBay would handle the financials, you were scammed.
EBay had nothing to do with the transaction.
How did you pay for it?
If you used Paypal you have 180 days from payment to file an Item Not Received Dispute with them.
The PP Resolution Centre is at the top of your account page under Activities.
If you used only a credit card, you can phone them immediately and enquire about a chargeback.
If you paid by debit card, gift cards, money order, personal check, or cash, you not only were scammed but there is no way to recover your money.