2010 Dodge Nitro Auto Repair

My car was in an accident and was repaired by an auto repair shop, my Insurance company sent me to. I have went through two set new tires since the accident. And could not find out what the problem was. I told it needed a wheel alignment, Which I gladly had done. Now I need 2 new tires for the back. I brought 4 new tires in July 2013. I was finally told when I got my oil change. That the frame is bent in the back. And that's why I keep buying tires. My point is the Auto Repair shop fixed the outside of my car. But not the bent frame. Which I did not know was bent. The insurance company drop me once my policy was up for renewal. Now I am with a new insurance company. Is the old insurance company responsible for fixing my car.