Showmax Cancellation

I subscribed to Showmax through Telkom. I do not have the Premium package and could not start Showmax. I then sent an email to Telkom to immediately cancel my subscription. Someone from Telkom phoned me the same day and cancelled everything for me. She also assured me that I will not have to pay for the subscription. I was so happy with this good service from Telkom but to my disappointment when I received my Telkom account the subscription was added to the amount I owe them. Needless to say I have sent several emails to them again with no reply at all!! What must I do to get a reaction from Telkom???