Excessive Debit Order amounts to theft!

We have had a data contract for 3 years. R 165 / month for 3 gigs. Having previously had a bad experience this account was never an open account and in 3 years we have never had additional charges. Last month a debit of R 13 000 was taken from our bank account. Vodacom is aware that the data is used by a ****le and an iPad and that sms messages are not received when we approach out of bundle. That however is irrelevant, the package was never supposed to be open, and I believe has been changed. Further, some sort of action should be taken when spending so far exceeds average spending. You have a primary contact number. Apart from that, out of bundle charges are so ridiculous they are nothing other than absolute theft. Finally, trying to sort this out by phone and mail has proven to be a waste of time. My mail has not had a response and I have grown tired of being transferred from person to person on the phone. We have cancelled the debit order and the bank has returned the payment. These devices however are used for work and our service is now compromised. Between my family and my company we have about 20 different Vodacom packages and have been loyal customers. But not any more!