*******, holding us hostage by blocking our business line

In November last year we took out a contract for a computer with vodacom. With it we got a free 1gb. We assumed the line caps at 1gb or at least we will get a message to say when we are nearing out of bundle. We went away in December to Jhb to visit family leaving the sim in the modem at home, which is linked to the camera. Like I say we had no clue that the sim is open as we were told we get 1gb free with the computer. Like any other normal person, you would think it cuts off when the data is up. The 1gb finished somewhere around the 14th of December without us knowing, while we were away, and we got no sms telling us this. The first sms we got from Vodacom was on the 31st of December saying that there's high data usage. So the last day of the month, when its too late to do anything about it, we get an sms. They slapped us with a bill of R7k for data usage!! Firstly we had no clue the line was open. Secondly, why does vodacom not notify when the data is being used out of bundle? Surely there is a law in place to protect consumers against this? We were unknowingly being billed for a service we were not technically consuming and which we had no use for. Where is the moral and ethical actions of this corporate? Is this how they go about making money? Fleecing the pockets of ordinary South Africans who are under enough strain as it is already! Seriously, VODACOM you owe South Africans more than this, it is disgusting!!!! We queried this bill from January, we lodged a complaint here with Hellopeter and got no help. We've been dealing with them telephonically but they keep giving us the middle finger by not hearing us, they just demand money. They repeatedly have blocked the business line, our business is stumped without this line, and they have blocked all our other lines that have nothing to do with this computer contract. They are adamant that they want this money and won't reason with us. We did not technically 'use' this data, we did not know about this open line, yet they refuse to meet us halfway...they just want to milk us for this R7****! A lady by the name of Jill is dealing with this, she has not once had the decency to pick the phone and call us. Funekha keeps saying she will call us, but in 6 months she has not done so, not even once. She's too busy, no time to do her job. Our business line is 20 years old with vodacom, we spend thousands with them monthly. Our business contract is due for renewal in July, rest assured it will be cancelled. If vodacom refuses to help us, we will be taking this to the relevant consumer protection body, because I've repeatedly said that we didn't even know this line was open or that the data was being used, we were not even in town, we had just left the sim in the modem. I would've got my neighbor to pull out the sim had I gotten any notification whilst I was away, that data was being used. There has to be some law that is in place that protects us from theft like this. Now they've blocked our business line, and halted our livelihood....until they get 7k? The business line has nothing to do with this, but they are using it to put pressure on us, so that they force us to pay for something that we didn't need or actually consume. This is highway *******. No ethics. I'm beyond disgusted and just sad that this is the state in which business is being done in this country.