Extensions from your main line, including all wiring and jacks, are your private property.
Somewhat off-topic:
Some people are charged for an item called "monthly jack/s" on their bills. These are charges for extensions. The reason why Telkom charges a monthly fee for extensions (which they acknowlege that the customer owns) is because they force you to pay a "mandatory" "free" "maintenance" charge of about R9/month. (Of course this is a contradiction of terms and makes no sense whatsoever.) Anyway....the very least of what all this means for the customer is that:
a) The customer may request Telkom to come and repair or replace any part of the extension (except end-user equipment, doh!) if it doesn't work - Telkom MAY NOT charge a call-out fee for this, unless the technician arrives and finds that there's nothing bloody well wrong with the extension in the first place
b) The customer who is paying a "monthly jack" fee to Telkom for an extension in their home could arguably tell Telkom to shove their "monthly jack" fee, because if something is owned by someone, you cannot force a "mandatory" "free" maintenance service on them. Telkom might remove the monthly charge, they probably won't.
[Either the customer owns it; or Telkom owns it and rents it to you. If the latter is the case, then this service, by definition, falls into the basket of services which are price controlled by Price Cap Regime regulation. By law, ICASA must first approve the inclusion of this service into the 'basket'.
Therefore, due to current non-inclusion in the 'basket' as well as the stated view of Telkom is that the customer owns all and any extensions, Telkom cannot charge this "mandatory" "maintenance" fee for extensions.]
c) Any customer in this situation should rather call Telkom and tell them that you will no longer be using the extension, and ask them to stop charging you the extension fee. Then just continue to use the extension anyway. I don't know if they can tell or prove this without coming to actually look- but even if they did come to look you are under NO obligation to allow them any 'surprise', not pre-arranged 'inspections', not least to parts of the line they consider belong to you!
d) Alternatively, you could call Telkom and tell them you no longer want to use the extensions, and that they must stop charging you every month for them, and that you will disable them yourself. Then have fun playing with the wires disconnecting things until the extension no longer works. If you still are not able to disable the extension, then just hack the thing out of the wall and sell the copper for scrap. It is YOUR extension after all (wiring an' all)! Unfortunately, it's also YOUR wall you're gonna be hacking to pieces, so you might wanna think this suggestion over whilst sober.
In circumstances b, c and d, telkom may not charge a call-out fee. PM me if you need reasoning why for practical use.
Sorry for going so Off-topic.