Incorrect Billing

I had cancelled my subscription with yellodata December 2016, I received sms that my subscription has been cancelled, every month they deduct my account R99.99 I have called written letters emailed but looks like my query is not going to be resolved, for the past 8 months I have reversed the amount by calling my bank, I have requested to speak to the manager or supervisor I get the same lame excuse " they are in a meeting" the last consultant said to me takes 31 days for a query to be sorted its over a 31days now and nothing has been done.!!!!