Wrong billing

In April 2016 MTN did not debit my account (R210) and they blamed it on that there were insufficient funds. I then paid the R210 at Absa Bank and I received sms's confirming my payment and MTN thanking me for the payment. They then suspended my line and when I called to find out what the problem was I was told I still owed them another R200. I signed for a R210 contract and I'm on the BIS plan but I was told I owed data for R200 which I know nothing about that and I had never requested for data from them and would not be able to get the data's from them as I'm on the BIS plan. the person I spoke to was Sunday Nkosi - Ref. no:***. now on the 29th of April MTN debited R772.81 from my account which I disputed. I then called and asked what the problem was and why am I being debited so much for a R210 contract, I was told it's last months money including this months money. I paid last months money at Absa and this months money they were suppose to debit only R210 and adding to that R210 x 2 does not sum up to R772.81. whilst on the call then the lady said no there were data's also included on that amount - again I'm on BIS plan. I asked how did go about requesting for the data's and she could not explain that to me. she then said the service has been activated on their side and she can see it from her side. I had never requested for any data from MTN let alone have ever spoken to someone with regards to getting data as I know what I signed up for. the ladies name isNosiswa Xhamele - ref. no: ***. I am tired of MTN messing up with my account and my line, they need to fix their problem and get their records right and straight.