DATA FEE USED TO INSANELY INCREASE YOUR BILL

I signed up with them for my business. R299 unlimited calls. NO data but I can buy data. So I ordered 3 cards and all went well until my first bill. It should have been R 897.00 but NO it is R 5799.00. So I chat with them and was told my credit limit was set so when data runs out it will take from my credit limit. I was assured I will not be charged for data and that I must buy a min of 50meg data per month. Never did I see this coming. They do ***** money by charging thousands for data that is not part of my package. I took unlimited calls and once off data. Never agreed to be billed like crazy for something I did not signup for. I WAS HOPEFUL IT WOULD BE A GREAT SERVICE BUT NOT THE CASE