If you found an ad on another site, and sent your contact information to a seller there, who responded that eBay would "handle the deal" -- then I am afraid you are dealing with a scammer.
That is not how eBay works. eBay does not rely on users finding ads on Facebook or other sites and sending contact information to a seller. Likely the seller will send a phony "invoice" that appears to be from eBay but is not, asking you to pay with gift cards to have the vehicle shipped to you for a free evaluation period.
eBay has no warehouse and does not ship vehicles. eBay does not handle such transactions or provide "vehicle protection orders". Scammers often promise those things, though. Any phone number you may receive on such an "invoice" does not connect to eBay, but to the scammer.
Anyone that asks you to purchase gift cards or to send card codes to them to complete a transaction is trying to take advantage of you. Anyone asking for a gift card is looking for a gift at your expense. Once anyone else knows the code, your money will be gone and you will have no recourse.
See here for some info about avoiding such scams:
https://pages.motors.ebay.com/buy/security/index.html
https://www.fbi.gov/scams-and-safety/common-fraud-schemes/online-vehicle-sale-fraud
The only way to purchase a vehicle on eBay is to sign in to eBay.com, find the vehicle on eBay and complete the checkout process on eBay. You may have to pay a deposit. Then you typically meet the seller to inspect the vehicle and pay the seller.
If you encountered an ad on another site, contact that site to have the ad removed. eBay is not involved with any ads listed on sites other than eBay itself.
