Brand new car 2017 model falling apart

I bought a Suzuki swift 1.2 from the Menley branch Pretoria in February 2017 in June we were standing the back window just shattered when we bought the car if you caught brakes down slope it shattered my husband thought its new car it will wear in to our mistake it got worst now we took it back and they said new disc has to be fit and we must pay R3000 rand it cant be a warranty claim Ive sent letters to there customer services stating that its a factory fault not wear an tear with no reply after 8 months for a car disc just to give in