Seller does not adhere to contract agreement

Hello, I don’t know exactly if this is the right area. Ggf please postpone. The following situation: I bought a passat about 2 months ago from private. According to the previous owner (seller) was among other things in the last 3 years coupling and timing belt renewed what made the car attractive to me. He said that the rep were made in a workshop, but he could not find the invoices. We then noted in the purchase contract under “other agreements” that he m I have not received any invoices yet, although I have already informed the seller several times by SMS. What is it like now? Is he obliged to send me the invoices? What can I do further? Would I have the right (only for the sake of interest) to withdraw from the purchase? Greeting CGTi