FAILURE TO CANCEL MEMBERSHIP!

I cancelled my membership with Planet Fitness on the 9th of December 2014 and had to pay a settlement fee of R1402.50, which I did and subsequently sent my proof of payment to the agent who was assisting me on the phone. I have since not received confirmation that my membership has been cancelled and instead have received sms's telling me that my account is in arrears. I have dealt with about 5 call centre agents who all promised to have this matter resolved, but up until now nothing. I have even tried to get hold of the person in charge of cancellations but was told I cannot communicate with him over the phone and I have to email him, which I did but still nothing. Today I got a phone call and was asked when I will be paying my membership fee for January. I am not going to send another proof of payment to another agent because they all work in the same place and should be able to trace what is going on. Someone that side is not doing their job and I am not going to do it for them. I would like to get an email AND a phonecall to confirm that my membership is cancelled once and for all. I don't want to deal with this anymore Planet Fitness.