Planet Fitness review: failure to cancel membership

I moved from upstate New York to Connecticut for an internship and immediately signed up for a monthly membership at Planet Fitness since it was the closest gym to where I lived. I had no problems while I went there. In October of 2011, I was preparing to move back to Rochester, NY so I went to the gym and verbally told the manager to cancel my membership, which he agreed to. I have recently (January 2013) found out that they NEVER STOPPED CHARGING ME, and after multiple phone calls refuse to without meeting in person or receiving a signed letter.

This is, again, after cancelling in person and receiving verbal confirmation of that. In other words, I have already performed the action stipulated by them. They continue to refuse to cancel my membership or refund the 15 months of membership fees they have charged since I cancelled.