Terrible Accounts

I have been a client with Vodacom for the normal contract period - I had the amount deducted every month via debit order. I have then requested that my account gets cancelled as I do not want to renew my contract with you. This was confirmed telephonically as well as email. I have received an email stating that they have confirmed my cancellation and that one more month will be debited ( THAT I WAS FINE WITH). Note that this was in 2013. Two years down the line I received calls from extremely rude attorneys telling me that I MUST pay the account and the last time they received payment from me was in January 2013 - knowing full well that everything went off debit order. I have never received any notice from vodacom informing me that anything has bounced. I have called you guys - spoke to a million consultants - a few has mentioned to me that my account was in order and that I should not be receiving all these calls and SMS's. Now I am at a point where I can no longer handle this anymore as I cannot get help from anyone and NO ONE LISTENS!!!!! I was this sorted out ASAP as I refuse to pay something I do not owe!!!