Terrible experience (considering trading in my VW)

After service(20 June 2015)I noticed a light rattling sound. Not being an expert I assumed it would go away. The next day the car started jerking and the engine was visibly shaking when I opened the bonnet. I decided to take it back the next day (Monday). Got their at 7am to miss traffic, was hoping car would be sorted by 10am (I was promised 11am). Guy came to hear the engine said it was my exhaust. After 2 hours I'm told my manifold was cracked and I have to replace it. I asked the manager how it is that my car ends up worse off after the service than before...aren't they suppose to check that the car is running smoothly? He gives me a quote for nearly R5000 including labour. The part alone was nearly R3000. They finished replacing the part by 5pm (10 hours of waiting for a serviced car to be fixed). I called about 7 times throughout the day to find out what was happening. At one point Lizo justifies his unprofessional behavior by apologetically saying, \I'm smoking my socks". A driver came to fetch me and he was visibly upset because we were caught in peak hour traffic. I thought this guy was suicidal. I've been waiting for a damage report since then to submit to insurance."""