Cancellation headaches

I phoned in to cancel my contract in October 2017, so my contract was supposed to end at the end of October (first of all, why can't I send and email, so that there is a written audit trail of the process?). I didn't receive any written confirmation, but trusted that the operator did what I requested. On 1 Nov 2017 I realized that I was still on contract, so I phoned again. They told me that the cancellation was not processed in October 2017, but since it was Vodacom's mistake they can do an immediate cancellation and reverse the charges for November 2017. This time I received a quotation (R 0.00) for the cancellation, which I completed and returned to the given email address. Today (4 Dec 2017) I noticed that my account was still debited for the full amount, even though I changed to prepaid on 1 Nov 2017 and the charges were supposed to be reversed. I phoned in again and eventually spoke to someone that wanted to transfer me back to the cancellations department that have messed it up twice so far. You make it extremely difficult and expensive to get hold of the right person to help with a query, the operators don't seem willing/able to carry out the requests properly and you don't provide any written feedback (have you ever heard of emails) to let me know what is going on. This sounds like a company that takes its customers for granted and it is therefore willing to take advantage of them - even after they have cancelled their contracts.