Vodacom data contract issue

Took a 2Gb data contract. Been working for more than 2 years on a capped basis. When data is finished, I get capped. This month suddenly I got a R5965.55 additional data charge.

Upon inquiry the call center told me that the data contract is open. I never gave instruction for the contract to be opened. They could also not provide me with proof that I authorized the contract to be open.

In the mean time one of my other numbers on the same contract came up for upgrade and they have called me 3 times already but for the problem no one seem to bother.