Terrible service

I purchased a brand new Chevy Utily from Fury GM Woodmead. After a week I noticed that the plastic rails on the roof of the car were coming loose. I called in and they asked me to bring the car in which I did. A day after collecting the car I noticed the same problem and called them. This time they fixed the problem but their attitude was terrible. On Friday 8th January as I was driving home in the rain I noticed water leaking into the car on the passenger foot rest. I immediately called the guy who was assisting me with the sales and he asked me to bring the car in on Saturday and get a courtesy while they investigate the problem. When I got there the service Manager (Chris) I have to book the car in since they didn't have any courtesy cars. I left the car with them and made other arrangements to get home. While all this is happening the attitude of the service manager and those around him was really terrible. Now I am without the car I purchased since they still have it for investigations and I also dont have a courtesy car. My work is really affected since I rely on the car for work purposes. What do I do?? :( :(