Over charging on bill

My debit order was rejected on 04/07/2017 for my data services. Payment was made on 11/07/2017. I then made 2 additional payments on 15/08/2017 & 22/08/2017. My monthly premiums are R 199 per month. After paying R 600, Telkom SA now says I still owe R 200. There is no help when I speak to the consultants & managers. They just say that I now need to pay R 200 more. I run a small business & this disruption is causing me to lose a lot of business & money. Telkom SA are a bunch of rogues. Even when I visited their branch at Gateway, the consultant there refused to assist me. Telkom's customer service is pathetic to say the least & all they are concerned about is making money. I have been a Telkom customer for over 10 years but now I think it's time to move to another service provider. The consultant also said that my data has been depleted, but I haven't used any data since 01/08/2017.