unauthorised contract renewal & undue enrichment

I took up the cellphone contract renewal for 2 of my cellphones on 8 April 2015. Due to non-deliver and/or bad service on the part of MTN, I cancelled the renewal of contracts. To my surprised, I received an invoice just over R1000. <br> <br> I then went to a number of their branches around SOWETO and Johannesburg, and was given different and conflicting responses to my issue, and countless calls to the Call Centre without any getting any headway with my query. In the meantime, my account was debited for May 2015 as if MTN provided a service to me. I then lodged a formal complaint via e-mail to Customer Care on 28 May 2015, under reference number [#***8]. To date, I have not received any response to this complaint.I then received the June 2015 invoice, to which I also lodged a formal dispute with Customer Care on 25 June 2015 under reference number [#***0]. To date, I also have not received any response.<br> <br> MTN is very quick to send me invoices and to debit my account timeously but it has to date failed to respond to any of my queries event though it has a \5-day response policy"towards lodged complaints.<br> <br> UNJUSTIFIED ENRICHMENT AT THE EXPENSE OF CUSTOMER SATISFACTION..."""