2 months after buying out contract Vodacom charges me R9500.00 with no reason or explanation.

I bought out my Vodacom contract at the beginning of December because I was immigrating. After almost 2 weeks of them not being able to find the payment of about R8000.00 they finally managed to cancel the contract and my number went prepaid. At the end of December they STILL debited my account as if I still had a contract and then re-credited the account when they realised their mistake. In the meantime I'm in Canada with no way of getting a hold of them because they do not respond to emails and the lines get dropped when I phone. Today I saw that my account has been debited with R9500.00???? What for???? I bought out the contract and received a receipt as well as a proof of contract cancellation from Vodacom. There was no airtime or data on the SIM card when I left? How am I supposed to sort this out with a 10 hour time difference and an absolutely disgusting lack of communication? I am horrified with this service and will be taking action should this matter not be solved soon.