Underbody Shield problems of the 2004 Jeep Grand Cherokee

I was pushed off the road during a snowstorm by a semi tractor/trailer and hit a cement barrier on i480 with my 2004 Jeep Grand Cherokee. Upon estimating the damages, I was told that I had left front rail damage that requires replacement. After 3 weeks the repair facility was unable to locate a replacement rail for my vehicle (they were told that the part was unavailable). On 5/11/05 I called daimler-Chrysler myself to find out what is going on, and why there are no rails available for a 2004 (one model year old) vehicle. I was told by the 1st person I spoke with (eric) that the reason a rail could not be found is because they are defective with welding issues and being recalled. I asked why I wasn't notified by daimler Chrysler and he didn't know. He took down all my information and said that he was sending my file to their parts department to do a world wide search for a rail and he would get back to me in a couple days. By late afternoon on 5/13/05 I had not heard back from daimler Chrysler, so I called back. I told my story to 3 more people that I was transferred around to, and the last person I spoke to was geoff, he was rude, tried to intimidate me, telling me that I had no business calling there, I was doing the legwork for my insurance company, and I told him that I had every right to call as I am the vehicle owner. Bottom line, they can produce a rail for my vehicle as early as June 1, 2005, but no guarantee that it will be that date. I feel that I have gotten the total run around and have been forced to use a rental car for 4 weeks now, because of daimler Chrysler's failure to provide parts for a 2004 model year vehicle which I understand they should have in stock for a 10 year period. (by federal law). I am totally frustrated by their lack of assistance and empathy for my situation, and want to know what recourse I may have against them or the government for failure to produce a part for a car that is one model year old.