Lose Power Steering problems of the 2016 Mercedes Benz CLA250

We have a 2016 mercedes c-300 vehicle that had a recall on the steering column concerning a latch bolt. Unknown if this recall pertains to the safety concern itself, after this fix the electronic communication system failed and causes this vehicle to lose power steering and would/can result in a crash. My family was traveling at speeds of nearly 70mph on the interstate and the entire steering system shut down forcing us to manually force the vehicle to the side of the road. When this fails, it will only steer straight ahead, if you are steering in any directions, you must force the steering wheel to right or left. Mercedes says their products often fails and this is acceptable. Everyone must understand when this fails this vehicle will only steer straight in the path it is going, if you fail to catch this in time, the vehicle will continue on the path to where the steering wheel is centered, if you do not catch this in time the force of the vehicle to stay on path is uncontrollable. The cost to repair is over $4300 and mercedes will not work to fix this or take notes to how serious this problem is.