NHTSA Complaint #11600131 — 2012 MERCEDES-BENZ C300

We are having issues when braking. The backend of the car wiggles when braking hard. Shop advised that the subframe on the passenger side completely broke away and on the driver side it is very rotted. They advised this is a safety issue since the broken side could pierce the gas tank. I googled this and found that there was a warranty extension for the same year and make car (document MC-10233796-0001) Spoke to the service department and they advised this did not apply to our VIN. I called the corporate number on the warranty extension letter and they advised the same. My complaint is that several other Mercedes models and makes have this issues and are covered. Why isn't ours? Based on images I found online it looks to be the exact failure mode. My son was supposed to drive the car 4.5 hours on the 4th and could have gotten into an accident or been stranded. I also read that in Germany they are fixing all vehicles with this issue.