Still Billed After Account Cancellation

I phoned to cancel my ADSL and Landline on 11 December 2014 and was told it would be cancelled on 11 January 2015. <br> <br> I have just received a bill for February for the amount of R 787.00. <br> <br> My reference number for my cancellation phone call is ***A. <br> <br> the phone number for the landline is ***<br> <br> The invoice number is 502A***u. <br> <br> I want these costs taken off my account!!!!