2013 AUDI S6 Steering Problems

I AM HAVING A MAJOR SAFETY ISSUE WITH MY CAR AND IT SEEMS LIKE AUDI OF AMERICA (AOA) DOES NOT SEEM TO REALLY CARE. IT ALL STARTED IN AUG 2015 AND A BUNCH OF FAULT CODES CAME ONE. THE SECOND TIME, I BELIEVE, WAS JAN 2016 AND I WAS DRIVING ON I-95 AND SUDDENLY ABOUT 5 FAULT CODES SHOWED UP WHILE I WAS DRIVING. I WAS TRAVELING ABOUT 70MPH IN THE MIDDLE LANE. THE CAR'S STEERING STIFFENED UP AND I COULD NOT ACCELERATE. LUCKILY NO ONE WAS NEXT TO ME AND I WAS ABLE TO PULL OFF TO THE SHOULDER. THIS COULD HAVE BEEN A MAJOR CATASTROPHE IF I WAS NOT ABLE TO PULL OVER WITH THE AMOUNT OF TRAFFIC THERE IS ON I-95 INCLUDING LOTS OF SEMI-TRUCKS. I TURNED THE CAR OFF AND TURNED IT ON AND I SLOWLY DROVE HOME. I ALSO DRIVE THIS CAR WITH MY NEWBORN...