Bad workmanship

I took my car into Supa quick on Friday for maintenance that was required on the exhaust as they had suggested I do so I got it done needless to say job was done so poorly after 1 day the whole exhaust system fell apart they blamed there supplier now today they did a quick fix again and my car is still not running well I call him back and he calls me a '****' very great service from Supa quick, I now have to take the car to a mechanic to get a diagnosis on what is damaged costing more money, I feel that Supa quick Randburg needs a serious wake up call