Can't get rid of Telkom!

I cancelled my contract on the 15th January. I got billed on the end of January. I followed up in store on the 13th February. Telkom says it takes 30 days to show on their system. I phoned the call centre, waited 30min. Telkom confirms it is cancelled, even gave me a reference number. 1 March, the number is still active. What must one do to get rid of this number!!!!