Terrible Service from Vodacom. Cannot cancel contract after expiry!

I am overseas at the moment and trying to cancel an expired Vodacom contract. No one answers emails! I can't call there customer care line from overseas. There TOBI app does not work at all and when you eventually get hold of a 'human' via the chat app line, they say it is not my department and cut you off. If you don't pay the account, Vodacom threatens to blacklist you. I have paid the contract and should now be able to cancel it, but Vodacom make it impossible to do.