1999 Honda CRV gasket blown

I bought this car about a month ago and the it started shutting down and smoking. The anti freeze was leaking. I took it to the shop because it kept shutting down. The mechanic said that the gasket was blown. The mechanic has had the car for about two weeks. He will not call me and when I call him back his asst. Says that they are still working on the car. I have called them over four times and I am not going to call them back. What are my options because my second payment will be due in another week. I do not feel comfortable in car this anymore. Am I still responsible for this car and what can I do to get out of this car? Why is it taking the mechanic so long to contact me? Do you think I should keep calling him? What should do in this situation please help?
thanks, Donna