Refuse to acknowledge cancellation

I contacted Vodacom to cancel my contract. First time they said they would, followed up 5 working days later and they had done nothing. Second time was sent a form which I completed, made payment and send to their cancellation dept as instructed by them. Followed up three times by mail with ZERO replies or acknowledgement. In the meantime have received latest bill with no changes and contract still open.

Should vodacom be listening kindly contact me by email as I am currently out the country.