Terrible service, *********** and negligence by Audi West Rand

On the 23 December 2019 I booked my car with Audi West Rand for an oil change service nothing major. During the day they call me with additional things they picked up that requires attention. For peace of mind I obliged and that cost me about R 12 000.00. I drive off and a day or two later I realized that the oil is leaking and I did not think its some to worry about after all I just serviced the car. At about a week later my car is asking for oil to be refilled. I had never had an oil leak before neither did they pick up such when my car went in. I phone them and because it was holiday time I refrain from driving the car and on the 06 January 2020 I go to the dealer and wait as they examine my car, in less than 2 hours I am told the vehicle is ready and fixed, I take my car and go to work. I park the car and our parking bays are so clean that a colleague noticed the oil leaking under as my vehicle was reversed parked. I phone the dealer again and we agree that I must drop it off in the morning, they want me to wait and I insist on leaving it since they said it was ok yesterday and it was not so that they can monitor it. I just got a call that there is a part that must be changed and they will order it and I need to pay for the part and they will take care of the labor. I told them that is not fair, since they were able to pick up 4 things unrelated to my oil service how come they did not pick up this part. I am informed that the mechanic saw it and did not think that its something to worry about, I find that hard to believe. All I know is prior to sending my car to them, I had never seen a drop of oil at any given time and I am not happy at all. At the same time I am thrilled as I will never service my vehicle with them because they are cheats nor buy car with them. Any mechanic in a dealer will jump to every opportunity to discover any damages to a vehicle so that they make money for that dealer, we all know that. The fact that they did not see this damaged part is problematic, the fact that only on the 3rd visit they inform me of the damaged part and make me pay for it yet 2 times they opened the car and did not see it now they claim they saw it the first time I came in and did not think its something major is more problematic. My oil problems started when I left my car under their care.