Poor client service experience

I'm at my wits end with Mondi Mobile. I have taken out a cellphone contract via telephone in Feb. The guy phoned me and misled me with the features of the phone. When the phone arrived it was not what I expected and returned it to a MTN direct store within 5 days as advised by Mondi Mobile. Ever since I have struggled to get this contract cancelled. They still deduct the contract money every month. I have phoned and emailed numerous times requesting a cancelation and refund with no success. They hardly answer calls. And whenever I get hold of them I need to explain the whole thing again but nothing happens. I have sent all cancelation documents through as well. On 27 August I received an email from Crescens Roland Varathan who said that my contract will be cancelled within 3-5 working days.... nothing has happened since. I have really received shockingly poor customer service.