VODACOM AGAIN

We had difficulties to cancel to extra numbers on my number. this was finally done. No new contact has been finalised on my existing number, I do not receive an invoice, no new contract, but if I enquire at the Secunda Vodacom shop I'm told there is an amount outstanding, and if I ask why as I did not receive a new phone , still have the previous one, the consultants cannot give me an answer that makes sense. How can you charge me monthly on an expired contract and not be able to justify the outstand amount. I have sent numerous emails to their accounts dept that don't have the manners to answer me back - And I do not talk to their computer. The previous issue also took months before I receive a call to sort it out