NHTSA Complaint #11445048 — 2015 CHEVROLET TAHOE

After a 7 hour road trip and returning to local stop and go travel in our hometown, the brakes started vibrating and the brake pedal then went hard. It took a severe downward foot thrust to get the vehicle to stop and even then still continued to roll forward a few feet. The brakes remained hard thereafter and not safe to drive- unable to brake at that point. Luckily we were not in traffic at that time or still on our road trip otherwise I am sure there would have been a serious wreck or fatality. Dealership supposedly took care of the recall repair for the vacuum pump previously but apparently their action was not sufficient. What am I supposed to do about it now? Thank you.