Billed for cancelled contract

Dearest vodacom, after months of fighting with you about my contracts, you eventually cancelled them after god knows how many requests.....and then you advised you would credit, my account/contract - my CANCELLED contracts - so basically i have credit in cancelled contracts that I don't use... how that works no one knows. But I left it, moved on, and then today out of the blue, again payment is taken off my bank account. REALLY??? i am in another country far far away and cannot come in to scream at anybody nor am I going to phone and waste more money on you guys.... legal it is. This is beyond shocking. BEYOND SHOCKING. What is going on? I need the payment reversed immediately.