My parked motorcycle was hit by a commercial vehicle in NY

My motorcycle was hit and ran over by a commercial truck while parked. I filled a claim with the insurance company of the truck (My insurance does not cover me for collision). The bike was declared totaled and they are offering me only 50% of the estimated value based on the argument that my motorcycle was illegally parked in a commercial parking zone. I feel that this is unfair, as in my mind the legallity of my parking is not relevant. For me there is no justification for hitting a stationnary. I also feel that the insurance company is taking advantage from the fact that I am filling on my own and not through my insurance and therefore that I might be tempted to accept their offer because of the cost of futher actions. What should be my next step ? Thank you for your advise.