Speed Control Cable problems of the 2011 Hyundai Sonata

On October 3, 2014, I had my car serviced for two Sonata recalls, one regarding the shift cable and the other regarding the brakes. That same afternoon, my stability control light illuminated on my dash. I have had this car for 4 years and could not remember it doing that ever before. Pressing the stability control button did nothing to change the light (it would not turn off). The next day, while pressing the gas pedal, I noticed a failure to accelerate. This has happened dozens of times since, at varying speeds, and while the car was both cold and warm. It always lasts several seconds and then I can accelerate again. During one of these episodes, I can press the gas pedal all the way to the floorboard and get no acceleration. This is becoming increasingly dangerous. I've been in to the dealership, and they denied any connection to the recall work, despite this problem presenting immediately upon leaving. They said they replaced the brake switch and that they should have charged me for that, but they did not. I got no paperwork showing that they actually replaced the brake switch. After that visit, the traction light was off for a day before this problem reoccurred. I am terrified driving this car to and from work because I never know when the acceleration will fail. It has happened while changing lanes in heavy traffic, and also on the ramps in my office parking garage.