MTN don't care about individuals, only money.

I've had 2 3G Mobile devices with MTN for about 2 years. They each cost me R101,48 for 2 gigabytes per month. My billing was thus constantly a monthly amount of R202,96. On 16 April 2017 I received a shock bill of R10 354,38 for one of the devices. I queried it with MTN and they just came back with a reply. The data was used and must be paid. MTN handed me over to VVM debt collectors who harassed myself and my husband on a daily basis via email, sms or phone call to pay the account. My lawyer wrote a letter to MTN legal department on September 2017 to explain my whole situation, but they didn't bother to respond. On my account there was a limit of R1704,57. My question is why didn't they stop the data usage when it reached that credit limit. Data is one thing they cannot prove was used. I contacted the SA Consumer Complaints company in November 2017 who set out to find answers from MTN. By April 2018 there was still no resolution with MTN. They referred me to ICASA for mediation. They were also unsuccessful in finding mediation with MTN because MTN just sent them what they sent me. It's bunch of numbers with the calculations reading as follows: ********** 80/1024/2014 = 354,88 MB x 0,87 out of bundle rate = R308,74 excl VAT. What am I supposed to do with that. I get an enormous bill out of the blue and after all my trouble of trying to resolve this matter, they have now handed me over to Hammond Pole attorneys for collection. They cannot prove that the data was used, yet they just don't care. I was blacklisted in approx July 2017. Does anyone have any idea of how I can resolve this since I do not attend to pay this amount to MTN, because they're big and powerful and can do what they want? Help please