Complaint Review: dora harding

I went on to facebook marketplace looking for a vehicle i came across this ad saying he was helping his family memeber sell this truck for 800.00 due to the death of her husband. she said ebay would handle the transaction they sent me a invoice i paid it with the ebay cards.

Then I was contacted saying it wasnt properly insured so another 600.00 was needed and would get it sent out immedialtely. here it is 5 or 6 days and no truck. Says ebay money back guarantee order 5635823005. what can I do?