Very bad service by BMW

I’m an owner of BMW M4 (2016 model) and since I bought that car I haven’t been able to enjoy it fully as it has been giving me problems. It has a very irritating noise when I press the brakes and it gets so loud at times that I get embarrassed. I took the car to BMW in Secunda more than 9 times now for the same problem and they were not able to solve the problem. The regional manager also came to Secunda to have a meeting with us and he told us that all the M4’s has the same problem and it will never go away completely. They sent us a letter referring to the owners manual that a noise will come out of the brakes but were never informed of such before we bought the car and we only got the owners manual when the car was handed over to us. Should we have known if such problem prior, we wouldn’t have purchased such an expensive car which would give us problems.