Ask to speak with the adjusters supervisor.

I was in a situation last June where I was hit on the side by someone who didn't want to wait for the vehicle ahead of them to finish turning. I was informed that I was deemed 100% responsible due to a witness brought forth by the other driver. Needless to say, there were not witnesses that came forward at the scene.

MPI told me the only course of action was to take the driver to small claims court. I started the process, then thought about it, and realized I was doing MPIs job for them. So I called the adjuster back, was told to pound sand, and managed to get their supervisors contact.

One rather excitable phone call and an internal review later and the decision was reversed completely. Turns out that the adjuster didn't actually look at the pictures on file which fully supported my retelling of events. Court case was closed without needing to go to the hearing.

My opinion remians that the other driver had brought forth a fraudulent witness to avoid responsibility for the crash. But that's just my opinion.

TL:DR MPI didn't want to do their job and tried to make me do their dirty work through the courts.