Zero Customer Service

My contract expired on 30/07/2015. I sent through a cancellation request to Mtn within the 30 day notice period. My account was debited again in September for this contract. I made numerous calls to Mtn and advised them of the error however to date I have received no emails, sms's or phone calls. I was advised by a consultant last week that my request was only captured at the end of August. I forwarded them the cancellation email and provided them with reference numbers I was given when cancelling, <br> I contacted them again this morning and was advised by another consultant that there was still a balance owing on my account. How is this possible. <br> I think it is totally unfair that I am being billed because of late capturing on Mtns side. I request a detailed statement and invoices as well as a refund.