Telkom sa bad service and follow up

Telkom service is disgusting taking advantage of people. In septemver 2020 i went to their shop in greenstone to find out why my bill was getting higher. The reply was i have used data. When i aporov3d the bew service i specifcally asked them how much i would pay per month they told me R348 pm. Not realising that after the second month my bill went up to R2000 and R3800 for no reason. They said someone would fone me which they did but after explaing the matter they said will come back to me. This happened 3 times to date still no reply, instead a call from the debt collector to recover on gehalf of telkom R8500. A service that i hve not used. Please help.