Telkom double billing

I received several call from agents at Telkom to move my ADSL line over to fiber. After 6 months of begging restarting my order I eventually got Fiber. From there on I got billed double every month for both Fiber and ADSL. I am so sick and tired of calling and calling and calling and calling. December I received back part of the double bill but low and behold on the next invoice I was billed double again. So we started the tang. on step forward 2 steps back. Every month a double bill. Every month a complaint. Every month a promise. Every month a new bill with both charges. February I upgraded to 20mps with a sworn promise from the agent that from now on the invoice will only be R 699. And I only have to pay R 300 as they will "fix" the mistake. I just received my new invoice. More than R 1000 rand again. What must I do to fix this. Telkom and its employees are totally ***********. I work from home and I have no other choice to pay the bill in order to work. how many other costumers do they milk like this. Maria Myburg. ***. My contact number is ***