Mtn changes contract without my knowledge

I have a couple of cellphone and data contracts with Mtn for longer than I can remember. In July I canceled my data contract as the bill went up literally every month. After my cancellation my top up contract (which I got for my child) limit was adjusted without my approval or knowledge. This is basically contract breach as the reason I got the top up contract was to have limits in place. Unfortunately when the first bill was sent through I was in a location with very bad mtn reception -typical-. So I missed the bill. The following month when I got the bill I saw that the bill was more than R2000 than normal. When I went back to the previous month I saw that the same had happened. This is where I wish I could complain about bad service as that would mean I have had SOME SORT OF SERVICE. <br> When phoning to get it straightened out all I that happens is I get send from one person to another. The past two months I couldn't even get a statement from mtn. When asked for a number for an independent govern authority to relate my case I was simply ignored. More bad news though mtn bills a month late so this month I am waiting for another shocker bill. Total money lost R6000-R8000.