Planet Fitness
Cancel form sent Sep, still charged 3 payments

I filled in a cancellation form and sent it 17 September 2013.
According to my calculations I only had a couple of months left anyway and requested my settlement amount.
I again requested my settlement amount in November and did not even get someone to phone me.
I noticed this month they charged me for November and even double for December even after I made it known that I wish to settle and end the contract by October 31st 2013.

Is this not illegal? I expect to be reimbursed in full for these 3 payments as this is unacceptable!