Car sells buyer sues for alleged lack of equipment

Hello, I sold my car and also called into the display the whole equipment of the vehicle. So it was obvious how the vehicle is equipped and has no trailer coupling. I did this with the VIN number. Now the buyer complains that I had cheated on it because the trailer coupling is not present, although it was inside mobile. I complete that I have placed 2 ads, once at small ads and at mobile and at mobile he has the A The buyer accuses me that I had cheated him with it, even though the buyer showed up with other people on site and checked the whole vehicle. He also drove the test with it and with an OBD tester he examined everything. Now he forces me, although it is written in the contract, to transfer money to him for the clutch. Au he no longer wants to register the vehicle as agreed (I have received a deposit for the registration plates and he would have received the money again as soon as the vehicle has been registered, is also in the contract) and says that he first wants the money plus the deposit and then first sign off. My question now: I wrote in the contract sale without guarantee, excluded liability etc. and the buyer could check, see and test everything on the car. Am I to blame now? Do you think I’ll do it?