Should he appoint a kaafir lawyer to get his money from the insurance company?

I am a student in America. A few weeks ago I had an accident and it was Allaah’s will that I suffer injuries in my back and shoulders. (The muscles are torn, according to the doctor, but he did not take an x-ray of my back in order to be certain). The accident was not my fault, hence the insurance company of the person who caused it will take responsibility for (repairs to) my car and my medical treatment, in accordance with the law. I tried to call the insurance company three times concerning the pain in my back and shoulders, so that I can get treatment at their expense, but they did not respond to me. It is as if they are trying to put me off and get out of paying.  Am I allowed to hire a kaafir lawyer to get compensation for the harm caused to me by the accident and for the disruption to my life – knowing that the lawyer may get compensation from them which may be many times more than the value of the car, and I do not know about the medical costs (which are very expensive in America)?