Billed incorrectly with no monthly statements

Telkom billed me incorrectly for over 3 month's with no explanation to this til last week when I called their help line. I cancelled my contract in November 2015 and it's not yet cancelled till today. To make it worse they don't even send me my monthly statements cause they know what they doing is completely wrong. I can not be billed so much for something I have cancelled. I've got voice recorders from their team saying it's cancelled and emails to show that I've sent my cancellation form. I'm really tired with Telkom and will not make any payments till my issue is resolved. I refuse to be treated in this manner and I refuse people taking money from my account without my authorisation.