Ebk service and negligence

Had a very bad experience with the dealership in La Rochelle Johannesburg . We bought a car which is a Chevrolet Spark the car temporarily in a good condition a month later a car had a gear problem and the driver's window was not working which was an electric window, it also had a clush problem. We then reported the issue and took back the car to have it checked out at the dealership because we had a warranty, the car came back nothing was fixed and they **** saying that they fixed it. We had to take it back again because the car was shaking when you reverse, they took it to their own mechanic, the mechanic didn't fix the car instead he used the car to drive around with it at night for his personal use. We then tried doing a follow up on what's going on because they were not communicating with us. They told us the can't fix the car and they customer service is very bad. They don't follow up with their mechanics. Their communication is very bad. We are going to open a case against them because they know nothing.