Out of bundle rates

I recently received my bill for January 2015, only to see that it had almost tripled. As it stands i pay between R900 - R1400 monthly with the majority of the costs being attributed to data. I regularly top up my data bundles once I receive an SMS from Vodacom advising me that I have exhausted my bundle. This month my bill was in excess of R3000, with my billing statement showing approximately R2000 worth of out of bundle data charges. I have called the Vodacom customer care centre and I was advised that I would have to pay an additional amount if I wanted to see a breakdown of my data usage. I was further advised that there is no limit set on my account, this was not brought to my attention when I entered into the contract, nor was I advised about the outrageous costs of out of bundle data. Notwithstanding this, I have always topped up within 24 hours of receiving the SMS from Vodacom that the bundle was depleted and I struggle to see how it is even remotely possible that I incurred such a hefty bill. It appears as though Vodacom are more than willing to let their \valued"customers fall into this trap. It is unacceptable that efforts are not made to advise customers of this."""