Telkom cannot cancel DSL service for 5 years

I moved away from Telkom DSL to a private WiFi service provider in August 2013 and have been trying to cancel my monthly Telkom subscription since then. I have a long archive of interactions, mostly including long waiting in queues. This morning I received my latest Telkom statement and lo and behold I am again charged R166.45 for DSL usage. Although I mostly encountered friendly staff when interacting with Telkom – apart from the very long waiting times – I am convinced that somewhere in the Telkom structure some organisational building blocks have become totally dysfunctional.