The only thing you could defend the trader on is that it was a trade in he was just punting on. U may also probably find it was the guy who traded it in to the trader that hid all the faults, traders just normally look at the car, Rev it up and check the history and mileage and take a punt on it. Buying a car you've never seen is also a rookie mistake; never part with any money untill you've checked the car over with it in front of you. Him not replying to your messages is out of order and he should contact u to see how he can help out. Bloody motor trade is full of schemers and assholes round every corner