BAD SERVICE when cancelling my contract

I contacted MTN mid July to cancel my contract, I was told to phone back on the 21st of July. I contacted them on the 21ts I was told I am supposed to cancel the contract after the debit order runs. I contacted them on the 28th, I was told that they have processed my request and my contract is cancelled. But there was no sms/e-mail confirmation of this. I contacted them on 07/08/15, the guy I spoke to doesnt know anything about my request. I was informed by this guy that someone was to contact me with 3 working days after cancellation, NO ONE did. I am very unhappy about your service as I will be billed more because my cancellation has been delayed. Please fix this mess... I dont expect to be billed more because of your miscommunication...