Inexperienced and unprofessional staff

Was wanting to sell my car a opel kadett. The guy that comes to check it was inexperienced, knew little about cars and just bull ****ted me. Takes the car for a long test drive and comes back and says my mileage is low because the speedometer is not working. I had to take the guy for a test drive myself and show him it's working perfectly. Go figure.. Then tells me the car is resprayed when a qualified paint technician and many people on the street praised the 1990 model car for being original. They should be aka we **** you into buying your car . Very disappointing and unprofessional.