Letter from the lawyer

Hello, I have the following questions for you and I hope someone can help me with this, and this is about the following topic: I (small car dealer) bought a Porsche Cayman S (half-year car) from a dealer whose private vehicle I sold to a customer from my workshop after a short time. The vehicle cost him about 70,000 €. This customer was then at the Porsche dealer and there he has his first annual inspection. There it was found that the vehicle was already a total damage and then his lawyer had sent me a letter, with the request to return this 70,000 € immediately to the customer. However, when I had bought the vehicle at the time, the seller assured me that the vehicle would be accident-free. Apparently that was not the case. 1. Then my question whether I was against the then salesman, who insured me with an accident-free vehicle, a And if so, a few tips or a good lawyer who can help me would be very helpful. 2. What would the same problem look like if a trader were to take me in the same way as a private man? What is brutally annoying me is the fact that through such “trotting” we traders have to fight for our existence and put our credibility at risk and I don’t see it that only the dealer is ALWAYS the stupid thing. I wish you another good day and I am happy about the letters and your help. Greetings Toni