HYUNDAI - FAULTY VEHCILE

I picked up a brand new Hyundai alcazar in September ****. soon after a month of driving, the car suddenly started facing issue which is critical safety concern. I was driving on the highway at ***kmh and suddenly there was a boom noise, the rpm soared to high levels and speed dropped drastically. just enough to be lucky no one in the car or on the road was injured. upon taking this matter with the higher ups, the company assured me to fix the problem and that it will not happen again. please note the process was not easy and I had to visit and complain as well as be on long call hours to fix my issue. Today, **th December ****, I faced the same issue while driving the car and this time the issue is much worse. The car has stopped responding to gear changes and is jerking as per its own. the car is behaving erratically on the road which poses the safety concern again for all people on the road. I, myself am not comfortable driving the car and demand the company to now finally replace the vehicle.