Frame And Members problems of the 2007 Hyundai Sonata

I had taken my 2007 Hyundai Sonata to towne Hyundai in denville, NJ. The xm radio mysteriously stopped working one day. Xm corporation had done troubleshooting with the car and determined that the signal was reaching the car and advised me to bring it to Hyundai. Hyundai noted that the top box for the xm radio which is located in a gulley in the trunk behind the rear passenger wheel had rusted and that there was water in my trunk. I was provided with a copy of a technical service bulletin that Hyundai had written noting that "water may enter the trunk through body seams, welds, body plugs" and that any suspect water entry point would need to be sealed to correct further damage from occurring. The xm top box is completely non-functional due to the water damage/excessive rust. Hyundai corporation has thus far refused to cover the defective body seals which is causing further rusting of the body of this vehicle as well as safety concerns if this vehicle were ever in an accident. Hyundai has also refused to cover any replacement costs relating to the xm radio top box. Hyundai has not been proactive in notifying customers of this defect and continually refuses to make good on its 7 year/unlimited mileage anti-perforation warranty for a defect they know exists.