Terrible customer service and damage to client car

I have been taking my cars for years to Bosch for services. I took my car for its 120,000km service to Astro Serv Bosch in Boksburg. Upon collection of my car I noticed that the leather part of the gear stick had been damaged by Bosch employees. This was never reported to a manager and the employee who took me to my car was also not aware of this damage. I contacted Astro Serv Bosch on the following business day and the workshop manager indicated they would only cover half the costs due to the milage of the car. I reluctantly agreed and then attempted to arrange a date for repairs. Over a month later and this has not been arranged by Astro Serv Bosch. I then started experiencing engine problems following the service. I took my car back to Astro Serv Bosch to find out that a spark plug they replaced in the service was faulty and this was then replaced with a new spark plug. I enquired about the gear stick repair and was informed the workshop manager was not there at the time and they could not provide me with an answer. My car now has a new rattling sound since the second time they worked on the car and I have tried to make contact with the workshop manager to find out what the problem is. I have left multiple messages and each time I call I am informed he is busy with a client and he will contact me later. After multiple messages I have still not been contacted by the workshop manager. I have rarely experienced such awful customer service and I am of the opinion that the workshop manager has indicated to reception to ignore my calls and not pass any messages on to him. After years of great service by Bosch I will unfortunately have to find an alternative supplier as the customer service level is non-existent.