Incompitant services consultant and poor workmanship

On the 11 June I had taken my car to William Hunt Midrand to have my brake discs, pads and water cooling system replaced due to leaking coolent, I was told by the service consultant that they cant finish the job cause they have too many cars which was nonsense, asked for my refund for parts they ordered, only after saying that they attended to my car. On picking up the car - there was a light flashing - did a quick diagnostic it was a CO2 sensor that cost R7000 to replace - took it to another independent dealer only to find the sensor had just shifted and needed to be placed correctly. Fast to September within three months the coolent is leaking again and now they are telling me its 1pipe they replaced + 2 other pipes behind the turbo that are leaking and I must pay for 2 pipes R4000 after paying R7000 for the cooling system , talking for real what shady work WHmindrand doing? I must complain and pay for their incompitant service consultate and technician! Get you act together am not paying for any nonsense will seek a reliable GM to complete quality and efficient work on my car.