Renault gate smashed by car and they refuse to fix it.

Took my car to Renault Midrand today. When i was driving it to the workshop the gate closed on me and the gate broke my mirror. When i went to fetch my car in the afternoon my mirror wasn't fixed and I was point blank accused of speeding and also trying to jump the gate. These accusations are coming from people who weren't even there. The people that were there are saying otherwise. There are no warning signs about the gate and where one should stop when the gate is open so that it doesn't close on you. They are adamant that their sensors are working. ******* service. I am not taking my car there again.