RENAULT SA (Pinetown Branch) broke my windscreen but won't fix it

I sent my car in for a service on 05 April 2018 and they serviced that parts that had to be fixed. I paid all the money they quoted over 3 months because it was around R24 000 and when the car was ready for collection, we found that they broke the windscreen. I decided that the car should be remain at the service station for them to fix it. When I called in around 10.28 am (11 June 2018), they (Nicky) told me that the person responsible (Mercia) was not around but they promised to call back. I called again after 30 minutes of waiting (11:11 am), and they said the same thing. It's now 01:31 pm and no has called or texted or emailed me.

No one wants to phone me back because they don't want to fix what they broke.

The service there is non-existent and their treatment is UNFAIR. They are taking advantage, especially when they know you cannot go into their office to complain everyday. I want the windscreen fixed and my car back. I also have a job and need my car.