Worst company to take a contract with

On the 20th of September a paid off my contract, they then debited my account. I have been calling mtn everyday for over a month each time iam being told the matter is with client retention, yet they never call or get back to me regarding this, iam sick and tired of calling mtn, my ref no is ***. I would advise people never ever take up any cellphone contract with Mtn South Africa the. Don't adhere to treating customers fairly. Even when u try and contact customer retention at mtn the do not respond, nor to do they pick up the phone.