Momentum refuses to cancel my medical aid after giving 30 day notice

Momentum refuses to cancel my medical aid after giving 30 day notice for cancellation. I called to let them know that I am cancelling my medical aid, the person I spoke to let me know that the medical aid is cancelled, then a few days later another agent called me to ask me why I cancelled my medical aid and I told her that I found better. This month they decided to debit my mother’s account, the transaction was reversed because I started with a new medical aid. I got a call from another agent a few days ago telling me that my account is in arrears, told her that I cancelled, she then told me that there were no records so I should email them telling them that I cancelled already, did that and now I have requested for my tax certificate through email because I couldn’t get it through their website, the person I emailed is telling me about the account being in arrears and not sending my certificate as requested, I then emailed back letting her know that I’ve cancelled the medical aid, she then told me that there is no record of my cancellation. I’m tired of this cancellation story, should you not cancel and send me my tax certificate, I’m taking this further because I don’t understand what is so hard about cancelling my membership, I no longer have want to be a momentum medical member, why are you forcing me to be one? The reference number attached is from the initial cancellation call