Impossible to cancel a Telkom fixed line contract!

We live in a housing complex of 14 homes in the Cape Town Southern Suburbs and, since January, no longer use the Telkom line for our entrance intercom. We completed the cancellation request documentation and emailed everything on 31st May 2918. So, as far as we are concerned, this service has been cancelled. Every time I call I am asked to forward the documentation again and none of my emails are ever rep**** to and I am never called back. The call centre is of no assistance. All 14 homes have Telkom fibre but, at this rate, we may be forced to look elsewhere for a reliable service provider. Any suggestions?