Hyundai Motors India Limited - Technical major fault in new car

I have purchased a vehicle Hyundai grand i** sports model dated **/**/**** registration number is HP ** E **** from Dev Bhoomi Hyundai Rajvir Motor Complex, NH-**, Kanlog, Shimla-****** H.P. But after one & half month around **** km there is a problem in the car. I went to the dealer and show car. He said that it's a major problem in car and said that leave this car for *- * days in the showroom. After * days I went to the showroom and he said that there is a major gear problem in the car he said that we repair this car or change gearbox & give him a one week time. I said that I do not agree to want this defected car because this is me & my family safety & give me a new car or my money back with interest because I am suffered from many losses. He said that this is not in our company policy we can’t change this car or don’t give money back. So I have registered my complaint at the National Consumer Forum my complaint no. is *******. From dated **-*-**** I am using a regular taxi for my daily purpose & my car is financed by Finance company I am paying interest & principal amount without using my car which is a great loss for me. I want my money back with interest & approx **,*** spend on my car.
Please solve my problem as soon as possible. I shall very thank full to you for your kind.