Overbiiled for Data I never even used

I've had my current contract with Mtn for 5 years now. For the last 2 years until May this year I had their handset and tablet (with 1GB data which I have never exceeded even once) for which my employer was paying them R800.00 direct. In May this year i upgraded both units and increased both my talking minutes and data to 2GB and my employer is now paying them R1 200.00 direct. My usage and behaviour hasn't changed at all but for some reason Mtn wants to debit my personal account over R4 000.00 every single month.<br> <br> My argument is how can I reach these amounts when I have a 24 hour internet access through my work laptop. After hours I use the company's 3G which simply means I hardly use my tablet or phone for internet access. So how does Mtn explain these ridiculous amounts?<br> <br> It took them about 3 months to respond to my initial complaint and the only thing they did is try to justify these bills. And all they did was send me threatening messages of service suspension and legal action. They didn't even bother to thoroughly investigate my case or even sit down with me.<br> <br> My service has suspended as we speak purely because I didn't allow them to debit my account.<br>