Accident. need to name tip…

Hello together.. I have mentioned a problem with an insurance, A few weeks ago someone drove me into the car, ( in my truck ) debt question is settled, opponent is to blame. BUT, my truck has a repair cost invoice from my expert 13000€ residual value is 6300.€ But since my car is in the 130 % regulation, I can have it repaired. That is not the subject.. Only the insurance paid me only the residual value. What I do not agree with… I have to have the car repaired. What I also had done (no workshop) is by a friend of the body builder. Now the insurance company has sent an expert, from which his report has come out that my car has not been professionally repaired… I DO NOT have used all new parts. My question, before I go to the lawyer.. Can I have an expert report on their costs?? Do I have to use new parts?? Or have I used the car. Least cards to get the rest of the insurance??? are still about 700€ How, what should I do?? I thank you for every tip VG Mario