Williams Hunts Centurion Bad Service

Just got a worse service in Williams hunt in centurion, it was my worse experience with the dealer after 5 years with them, I took in my drivable car for minor service on Friday 01/03/2019, they called me around 12 midday informing me about things I need to replace on the car, which coil pack was one of them, which I said I will bring it in month end so it can be replaced,which they have opened it for inspection, they quoted me R3900 to replace it, later they called me to come collect my car, it was ready, after leaving their premises, say less than a kilometer, I saw an engine light, I immediately called Micheal Minnie informing him about engine light and said to me it's coil pack he quoted which needed to be replaced, so I ignored the light and drove, I got stuck 2 kilometers, I couldn't drive the car, I drove around with my car and never had issues before taking it in for service with them, it looks like I paid them about R2500 for washing my car not for servicing it, I was told my car was not drivable before it came in for service, I drove it from Pretoria west to centurion, now they are telling me I can't prove that. Bad service ever