Cannot cancel my contract

I took a contract with Planet fitness (24-month contract) in January 2015. In December 2016, I upgraded my account to black tag. I have been calling from April 2017 to cancel they said my contract will expire in December 2018. I did not receive any feedback regarding this. I called numerous times and all I was given was a reference number.

PF ********** PF ********** PF **********

I do not know what else to do. I do not even attend the gym any longer at Planet Fitness. What else must one do to get recognized?