Brake Grinding Noise problems of the 2013 Ford Fiesta

I purchased the vehicle used in February of 2014. A couple of days after having the vehicle it started to make loud grinding noises, when I tried to accelerate it would sputter and almost stall. I took it in on March 05, 2014 and the dealership had it for a week. When I picked it up, I was told that they could not find anything wrong with it and the grinding was "normal". The grinding noises, the sputtering, the slow acceleration, and other issues are still happening with this vehicle. When I call to see if I can take it in, I am told that this is normal for this vehicle. These 'normal' attributes should be disclosed prior to purchasing the vehicle. When I am at a stop and I start to accelerate, the car does not accelerate and it lunges and it has caused me to almost get rear-ended on more than one occasion. There has been a couple of times where I am driving on the highway at a steady speed and when I try to accelerate, it does not accelerate and the rpms just shoot up. The transmission of this vehicle has too many bugs in it and it is causing a safety concern. If I would have known that these things were 'normal' prior to purchasing the vehicle, I never would have bought it. Something needs to be done about this. I have seen numerous complaints that are very similar to mine and it truly is a safety concern that needs to be addressed.