Refusal to Cancel My Contract

I called the customer Care Call Centre to inform them that I would not be renewing my contract that was ending that month. I was told that they would send an email to Retentions and that they would get back to me. I was also given a number for Retentions Dept that was no longer working and another landline that never gets answered.<br> I didn't hear anything for another 2 weeks so I called again after my account was debited and was told Retentions said they couldn't cancel my contract because my account was in arrears but they had no record of me ever missing a payment.<br> Then another 10 days later I was told Retentions refused to cancel my account because I'm due for an upgrade which I vehemently refused. So they said they would move me back to prepaid within 24 hours.<br> Lastly I called again and was told by a Customer Care Team Leader that this matter would be dealt with urgently and still nothing has happened 6 days later. And my account has been credited with airtime again.