Telkom changing contract terms without your consent!!

Telkom adjusts your contract terms without you having a say in the matter. They added "extra data" to my supposedly "capped" account. I have a huge bill now, and the account is suspended due to non payment (because I will not pay for something I never gave consent for and I was not informed of this extra data that was being made available to me). I've been struggling to get a copy of the signed consent (which I know for a fact I never signed any consent) or a copy of the voice recording where I consented to this extra data (again, I never gave any consent, not in writing or verbally). Apparently I will need a court order to obtain a copy of the consent (which I say again, I never gave them any consent). Upon asking for a breakdown of the data usage to ascertain who used this data, seeing as though they can't (won't) let me have a copy of the consent, they "could" not supply me with a data usage report. It's been weeks now that I've requested they write off this amount, because they can't give me any proof of either consent of show where and on which sites this data was used. Every time I just get an email back saying it has been referred to the relevant department. This contract has to be cancelled as the 2 year period is over, but I cannot cancel it because there is an amount outstanding. Now, I have to pay a monthly fee for something I can't even use. It is sad to see how these companies have all the power and the loyal clients just has to accept it.