Wrong Car!

I booked a 25 000km service at Audi Centre Centurion on Monday 18 Sep. 2017. Upon arrival, I was met with a gentleman in a white coat, very professionally. Upon entering the reception area the service consultant did not have my paperwork ready and had to search for them. I specifically asked for a quote on a navigation system as my A3 TFSI doesn't have one, and to check my aircon as it is not blowing cold air. During the morning I received a phone call saying they are working on the car, I enquired about the cost for the navigation system. The service consultant said he was waiting for a price. Around 15h00 my car was ready and the driver picked me up, no problem. Upon entering the reception area, once again the service consultant could not find my documents. Upon finding the required paperwork, he very quickly told me that my car is serviced and ready to go, I don't have to pay anything as it's covered by the maintenance plan. Once again I enquired about the cost of a navigation system, which he told me there is no navigation system available for the Audi A3, which I found strange as there is a button on the MMI System for Navigation and should be an optional extra. But he insisted there was no such system available. I checked on Wheels24.co.za and there definitely is a navigation system one can install on the A3. He said he would collect my car and I waited outside. The service consultant arrived with an Audi A3, but not MY car! He gave me the keys and said goodbye. I then pointed out to him that this was not my car, and I would like my own vehicle back. He just looked at me and said it's a busy day. He fetched my car with not much of an apology. Over the past weekend, I was cleaning my car and found an extra set of car keys in my drink holder! They belonged to a Mr. Van Heerden, registration number DNxxSZGP and I can just imagine the pandemonium at Audi Centurion when Mr. van Heerden took his car in for a service, and the garage lost his car keys! Surely Audi should have better quality control measures in place when handling clients car keys! Misplacing car keys could place the client in danger as car keys and vehicle registration number can be sold to *********. This was not a pleasant thought. I phoned the dealer principal yesterday, explained my situation and told him that Audi can learn a great deal from Toyota Centurion South Street with regard to customer service when servicing a car. I will rate Audi 2/10 and definitely not go back. At least the dealer principal apologized for their bad service and sent a driver to collect Mr. Van Heerdens car keys.