PLANET FITNESS KEEP DEBITING MY ACCOUNT

I cancelled my membership at the end of 2013. I have it in writing from Chrislynne at Rivonia branch (she no longer works there) that they agreed to cancel my membership as well as the debit order. All of a sudden in December 2014 they debited my account (I reversed the transaction and they debited my account two weeks later again - I reversed it again). They have debt recovery companies on my back threatening me. All attempts to contact the planet fitness call centre are futile. I once got through and spoke to Khoketso who asked me to send her the proof that they agreed to cancel. I sent the email to her but there has been no further reaction from them. In the meantime I continue to be harassed by the debt collection agency. Fitness companies cannot seem to handle when clients cancel subscriptions. Can you help me - this is so frustrating