Brake Disc Pads problems of the 2011 Ford Taurus

I purchased my vehicle adn after only 15,000 miles I visited the dealer for a grinding sound on the brakes. Ford recommended that I had to pay for repair on the brakes because the pads were almost gone and I told them that it was impossible because I do not brake that much since I use the vehicle in the highway most of the time. After the car was repaired I had to bring the vehicle back for brake repair only after 4,000 additional miles and they told me the brakes were fine, but I told them that the brakes were failing because the I had difficulty braking and had to press them too hard to fully stop. I have almost crashed a couple of times, but I fear that if I have to perform an emergency stop while the brakes are hot I will crash. I took the vehicle for a second professionalo opinion and they told me that the vehicle is too heavy for the braking system. In addition, Ford modified the brake system in 2013 models and added 30% more braking space on their rotors. I believe they know about this defect and have ignored this situation. They have worked on the car more than six times and nothing. When the brakes get hot the rotors get "crystalized" and then a humming grinding sound starts followed by "sponge like feeling" on the brake pedal. I have changed the pads in three occasions and the car has only 54,000. I am going to file a complaint with the consumer department because they refuse to take the car back. I even had to purchase a new vehicle because I fear for my safety and my passengers. Please help any way you can. These people are just reckless. This is a 365 horsepower twin turbo Taurus and it does not properly stop after the rotors "crystalize" I have tried everything with them. This is supposed to be their "top of the" line model.