Telkom refusing to cancel my service

In September 2017, in order to cut some costs i decided to move my pay as you go adsl line back to telkom and use their unlimited package instead, i have had ADSL for a while now and have a ADSL router. I went to see the Telkom branch in Kenilworth centre where they upgraded me to a 24 month contract so i could get a free fibre router as there was supposed to be fibre by the end of September. Since my income is dependent on a working internet connection and Telkom could not provide me with a stable connection, i was forced to find a new service provider in January. Since January i have been trying to cancel my Telkom service with no success. Telkom has been making it impossible to cancel my service, and is most likely trying to keep me in a contract, that i didn't need as they never provided me with fibre internet as promised for which they locked me into a contract. I cancelled my service 3 times already and nothing has happened.