Is it legal to pay someone majority of the money on a vehicle you both agreed on and the person refuses to give you the vehicle or your money back?

I meet with someone who was selling a vehicle online and when I got there we agreed that I would pay majority of price for the vehicle so they would hold it for me. They agreed to those terms. That following week I they took the car to Midas auto shop for a full diagnostic and Midas informed me that the car is a lemon. They then said that I'm not getting my money back or the car because they didn't trust Midas's opinion.