Disgrace, Can't even fix a bumper

My car has been with Renew-it Rivonia for 3 weeks. They are just fixing a bumper. They refused to put a new one on. They will fix the old one. They promised me that the car will be done today. Today they phone and say that the bumper can't be fixed. They have to start over with the assessment process. This is a third party claim. The other person's insurance won't just accept the new quote, since the process was signed off allready. I am without a car for 3 weeks already, paying for a rental. Renew-it insisted on fixing the old bumper, Now, 3 weeks later they say they can't.

Complete disgrace. It's just a bumper. Is this the first bumper they are fixing?