Zone Fitness agents harassment and ******** treatment

Zone fitness agent named Tracy signed me up by lying to me about when to pay and how I could pay. I decided to cancel my contract with them after 2 weeks of being in the gym then they asked me to pay the cancelation fee even though I told them that I don't have any money. I'm a student and I'm only 18 years old. How will I pay it. Not only that, this agent has been harassing me calling me 5 times a day!