2008 Chevrolet Suburban Steering Problems

I have a 2008 Suburban. Beginning in August, there was an accident on the highway and traffic was backed up. I was idling, waiting for the traffic to move, like every other car on the hightway and the suburban just shut off and said "Stablitrak off." It happened numerous times after this, just when idling. I took to the dealership I bought it at. They charged a ton to fix something but it didn't' take care of the problem. It's gotten so much worse. I took back a few months ago and they fixed it again, but didn't charge us this time. Now it's so much worse. Anytime I'm iding, just picking my daughter up at school or just stopped at a red light, a warning comes across, "service stabilitrak" or "stablitrak off." and the car immediately shuts off. It usually restarts in 5 minutes or so and I can usually make it to my destination as long as I don't idle again. Monday I was picking up my daughter and it stalled in the parking lot at her high school with tons of cars behind me- I waited, restarted it as I have done in the past. But then, going down this steep high school hill, the car shut off, lost steering and brakes wouldn't even work. I had teen drivers ahead of me that I nearly crashed into, teens in my car. This is not ok. We took it back to the dealership and now they say it's an electrical problem. I've read a ton online forums that this is something that happens with a lot of other people. I'm afraid to drive my car. I'm also not sure what to get fixed because these other people have spent tons of money, just like me with no results.

TL* THE CONTACT OWNS A 2008 CHEVROLET SUBURBAN 1500. WHILE CHECKING THE BRAKES AND REMOVING ONE OF THE TIRES, THE CONTACT NOTICED THAT THE CROSS MEMBER THAT HELD THE STEERING STABILIZER BAR WAS RUSTED COMPLETELY THROUGH ON THE PASSENGER SIDE NEAR THE BOLTS. THE VEHICLE WAS NOT DIAGNOSED OR REPAIRED. THE MANUFACTURER WAS NOTIFIED OF THE FAILURE. THE APPROXIMATE FAILURE MILEAGE WAS 114,000.