If my insurance company put me at fault but I have proof that I wasn't at fault, how can I fight it?
Question Details: I have proof that the police report was a lie. I have the police camera footage and audio proof that the witness didn't see anything but the aftermath.
What do you mean by "fight it"? If you are being sued by someone due to the accident, you can defend yourself in the lawsuit by showing evidence that you were not at fault.
Or if someone (your insurer or the other driver) is refusing to pay you when you believe that you were not at fault in an accident and should receive compensation, you can sue the other driver or your own insurer (if they are not honoring your policy and paying your claim--you would sue them for "breach of contract," since an insurance policy is a contract).
But if you mean that your insurer is paying the other driver because they believe you are at fault, there is nothing you can do. It is your insurer's right to settle claims if they believe their driver is at fault, and you have no right to interfere in their decision to do this.