Incorrect Billing

I had a contract phone with Telkom for 24 months and when my contract was on the 23th month I requested that they should not renew but cancel it. I went to the Brooklyn branch to apply for cancellation as they indicated and while my form was submitted waiting for the 21days for it to be activated I was billed for that account when I queried it they said they didn't receive anything and I went back to the lady who helped me and we send them the form as proof they opened the case yet still deducted the money in my account it's been a month while I am waiting for their response they still didn't come back to me and I dispute the payment because I told them I won't pay for something I didn't request for. I opened another account for the R99 rooter and the lady made it clear to me that there is add on internet data and if I don't want it I should cancel it,I did so and it was included in my account yet Telkom keeps billing me for something again I didn't request for and I called so many times to fix this matter and they don't even have an answer why is like that. Even today I received a statement still including what I never requested for. Please assist in this regard.