Telkom billing no service

The Telkom cables in our area was ****** last year around August. Telkom notified us that they will not be replacing the ****** cables and that our DSL services will be suspended. I canceled my DSL account with them, just to realize they never stopped billing me. On the invoice it states that we have no service in our area, but they are still continuing to bill me for absolutely nothing. I have tried to get a hold of them, but it's like speaking into a black hole in space.