Workshop with no experience!!!

On the 22/09/2017 i sent my vehicle in to be serviced at the Umhlanga branch. The mechanic opened out my tyres in order to check my braking system, they informed me that my brake pads need to be replaced. On the 03/10/2017 my husband noticed that 3 of the lock nuts that hold the tyre in place were loose (driver side front tyre). He tightened 2 of the nuts and discovered that 1 was cross threaded, due to this he was unable to open/ tighten it. I called the workshop on the 04/10/2017 to complain and i spoke to Rodney he requested that i bring the car in but i was unable to on the day as i had just gone back to work after a period of leave. I requested that the manager (Adrian) call me back to date i have not received a call. Unfortunately i was unable to go to the delearship due to work constraints. On the 28/10/2017 i had new tyres put in and when they opened the nut that was cross threaded it broke off. My husband and I went to the dealership on the same day (28/10/2017) as it was not far away and we spoke to a very helpful salesman James, unfortunately he could not assist as the workshop was closed and advised us to contact the workshop when they reopened. I went on holiday to Mozambique and was unfortunately unable to resolve the issue immediately. I called again on the 04/12/2017 and spoke to Armstrong and informed him of my issue he promised that the manager would give me a call back and still to date no calls. I am an extremely busy professional and i do not have time to chase the incompetent managers. I need the stud replaced immediately. I also want to mention that fact that i drove around for a few days with a loose tyre which could have cost me my life had the tyre came loose whilst i was driving on the freeway. If i do not receive a response today I will be contacting my lawyer.