Faulty brakes on my Chev Sonic

We bought our Chev Sonic in February 2013 from GM Menlyn. Al went well until a few months later when the car's brakes started acting up. When braking the steering wheel would vibrate and the brakes made a noise. We took the car in on which they replaced the brakes and explained al four brake pads were faulty and sent back to the manufacturer. As times past the car started having other problems on which I took the car back but every time they said they could not find the problem. <br> The last straw was about two weeks back we took the car back as the brakes failed twice and the car basically died and I nearly drove into a gate. After having a look they gave us a call and said the brake pads have about 20% left and it will cost R3 500 to replace al 4 as well as fix the back brake drums as they are scratched. <br> The problem now is this will be the THIRD set of brake pads sins we got the car and it is not even three years old yet and only have 46 000 kilos on which means we only get about 15 000 kilos on average out of the car a year. Even their mechanics said this was not normal. Sort story is I am still waiting for feedback and driving with a car with nearly no brakes!!! Great service!!!