Garden city....poor service

Sent my vehicle in because the rear wiper wasn't working...stopped the car off at 07:45....and didnt recieve feedback until 15:30. I made 9 calls and spoke to 3 different service advisors and non of them gave any help. The service is absolutely appalling...one would think that mercedes benz would treat its customers better. The worse part is that they are the only mercedes dealership in PMB. So we have no other choice.. god help us...