Death Trap by Mercedes Benz

I recently purchased 2014 W205 C220 bluetec, currently still under motorplan, 64000km on the clock. Early December when I was driving the vehicle I suddenly lost steering to the car while I was driving. All I can do was brake and stop in the middle of the road. If this had to happen on the highway at highway speed, I could of had a big accident, or worse! I complained to Mercedes Benz SA, no response, I had to chase the dealer for information. Complained to Mercedes Benz SA again, I stressed to them the seriousness of the fault, as the vehicle is used mostly by my wife transporting my kids, they are afraid to use the vehicle as they fear it might happen again, answer I got from Mercedes SA consultant was "if you not happy with the vehicle, return to the person you brought it from"!!!! This is totally unacceptable!!!!!! Especially from Mercedes BENZ!!!!!!! Till now I still don't have my car bac****!! Mercedes Benz Case Number 1- ********** 6971