Doing their job and get charged extra on my contract

Ever since i started my uncapped wifi contract with telkom i had problems with the amount not being the same as the amount i signed for on the contract. Went to the telkom branch in matlosana where Richter assisted me as far as he could for the store does not work with billing. He put a request in for me so that they can phone me for the number when i phone does not work. Spoke to a lady from HO and now they say that ita due to the usage i use. What usage is there when i dont even have a phone connected to the line its in the router. I signed for R849 not more than a R1000 every month. They cant put me through to billing i have to phone them. Lady gave me a number and its the exact number i tried phoning the whole morning. I told the lady hold on while i dial this number its not working. And it didnt work. She advised me to go back to telkom and go put in a request so that they can phone me again. Are they gonna pay my salary for doing their job during my working hours? They just gonna have to disputed all the money paid extra on this ****** contract and sending me up and down. Still waiting for my recorded phone conversation that i asked the lady for.