Billing issues with telkom

For the past 3 months I have been over charged on my telkom account. I signed up with telkom in 2017 on an ADSL contract for R799 per month for 24 months. Obliviously with the tax in crease the installment went up but this is not the issue. As i said for the past 3 months i have been having billing issues where telkom is charging me double to almost triple my monthly installment, i have called many times and yet no concrete answer. I eventually contacted them on facebook where i finally got an answer via their facebook messenger page. They then informed me that the issue was sorted and my new billing information would be available as of the 09.11.2018, yet after receiving this bill i was still to pay over R1000 for the month and on top of it all i am told that i owe them R400. I am concerned that some type of ***** is being committed on my account and would appreciate a honest answer in this regard.