POOR SERVICE DELIVERY

My car was involved in a car accident about a month ago, and Momentum appointed panel beater ( Breden Auto Body) to fix the car, and i was also granted a coutersy car for a month. The panel beater said the estimated finish date was the 09/010/15. Unfortunately my car is still not fixed and when i request an extention on a hired car from momentum, they can't help me and the panel beater doesnt have any spare cars. My problem is Im paying momentum every month and now they do not want to grant me an extention on a coutersy car and they are saying I should talk to the panel beater which they have appointed. This is affecting me because I use the car for work purpose so right now I have no car and my insurance people are not willing to help. All I need is for Momentum to assist me in getting an extention on a hired car, since the very same people who were appointed by them are delaying with the car.