Bad costumer care.

I took my car for service. I was given a qoute, on Friday and I was told they will order parts and will fix the car on Monday. On Saturday after consulting I changed my mind I called to cancel, I was told the workshop is closed, On Monday 7Am I was at the dealer I was told my car was already fixed I must just pay up. They gave me a run around untill 11. The thing there was no need to change the engine mounting. This is the second incident. I had a problem wit the sensor of the wheel, I took it in for about 6 months. I ended up taking my car to Midrand. I'm actually feeling ******. I don't know what to do. Am I not we not allowed to change my mind, before the word is done? I have a Toyota car I took it for service in several dealers and All the time I get a clear explanation and very good customer care. To be very honest Centurion is very bad. Very bad attitude, I did comment to them before.