Car Service City Celtis Ridge Centurion review: No results as they are so rude with me, have reported it to their head office, no reply

On The 17/10/2023, I gave my Audi A5 sports back for a major service, as per the invoice they charged me for 5w40 oil, oil filter and air filter, r2795.00 when I took my car home it started smoking from the exhaust (white) car was misfiring, I took it back to them the same day, showing them what they have done, they threw me off the premises, stating it is not their fault

I went home draing out 7.5l of black oil which was one day after the major service, should the oil be black after one day,? Which they did not change at the service, I have proof., there was only 5l that needed to be put in, this resulted in my oil pump packing up due to a blockage and overall on the engine as there was a knock