Vodacom's exhorbitant data charges

Further to my previous post regarding the 20 gig contract foisted upon me in place of the 30 +30 gig contract I signed up for, the following. I have discovered that if I would like to "top up" my inadequate data, I would have to pay R100 for every gigabyte of data. This is 1000% more than the charge for the 20gig I receive every month on the contract!! This is ludicrous!! Surely this contitutes an unfair business practice? Obviously, this is how Vodacom generate their exhorbitant profits!? I am in a good mind to report this practice to the consumer council!? Shame on you Vodacom!