Used car from the dealer: 8 workshop visits, should only get 4tEuro instead of the purchase price

Hello together explanation: I bought a car at the friendly in January this year. I let him finance it. I have this car now 7 months. In that time the car was about 7 times in the workshop because of the SELVEN problem. I talked to the seller last week and told him to take the car back.Then he wanted to be “smart”. Today I was with him. He told me that I would get 4000Euro for the car.For the car 7 months ago 7000Eur o paid. But must pay for the loan still 4600Euro. Because the dealer does not get the car repaired and I have after 8 workshop stays the snare full I should make a loss business of 3000Euro. Now I called the ARAG. This led me to a lawyer. The following has been told to me: I have a right of withdrawal after 2 attempts The following paragraphs (hope I have written correctly) are decided for me: 433 434 437 NR.2 440 v binding with 323 BGB Should the dealer sit down a eaten of 1week. Now I want to know if the dealer definitely has to take the car back? Will also make an appointment with the lawyer tomorrow to send the dealer something “beautiful”. But would like to inform me before what it looks like. And what exactly do I have to take with me to the lawyer? Many thanks MfG Christian