Poor service from grand central management

A bought my car from Grand central Mercedes Benz Midrand in the 18th of January 2019. I had lots of problem to mention a few: a leaking roof, noice on the doors, radio, and the drive sit was not working. Later some of these were fixed however the roof still leaking and that for me is the main problem. I has a discussion with the line manager who then referred me to the dealer principal. We had couple of discussions and we agreed that the car should be brought back when the auto boby opens now January 2020. Suprisingly I got an email from the dealer indicating that roof will not be fixed by them as it is expensive. I'm disappointed my the service as this was an issue that went on for the a year. They could have told me then when I reported it that, they will not be able to fix it. I'm still sitting with the problem and it's a raining season. I'm very frustrated.