horrific service , contract cancellation

I am frustrated and disgusted with the horrible service received from telkom mobile, went into clearwater mall branch 04/14 to cancel contract, followed up constantly, called cancellation department, spoke to Zama Gumede and P Mzimel , sent them proof of cancellation, sent numerous mails and no feedback, my mails are being ignored and im being billed for a contract i no longer use, sent mails nov 2014, dec 2014 , jan 2015 and still nothing .i refuse to be held responsible for the amount due.