Auto insurance provider not thoroughly investigating my accident. It wasn't my fault. How do I proceed?

I was rear-ended after backing out of an alley. I was no longer in reverse gear. Insurance absolutely refuses to pull EDR to help determine fault. I obtained video surveillance footage and zoomed in on the other driver 7 seconds before the collision. He was turning right while looking down at his phone, which he was holding in his right hand between his chest and the steering wheel. In the vid, it is clear he never hit his brakes; he didn't use his brakes until after I did, when the collision happened. He didn't swerve or flinch when he saw me enter the road. As if he didn't see me because he wasn't looking out his windshield, he was looking at his phone. The impact broke my rear impact bar, which cannot happen from a low-speed T-bone collision. He hit me after I had backed into the street at an angle. when he hit me, his momentum kept in the forward motion across my rear bumper turning my vehicle to be perpendicular with the sidewalk and parallel with the alley which made it look like i had T boned him while backing out of the alley. I had already shifted out of reverse and was looking ahead of my vehicle when the impact occurred.