Possibly a lot have transitioned to VoIP because of copper theft. VoIP usually gives an engaged/unavailable tone (or 404 hangup) if the SIP hasn't registered.most of the time those phones do not work because the cable she was stolen, and Telkom will not replace it either, so all they do is put in a single LTE modem, throttle it to nothing, and connect the komputahs to it, the phones are still on the stolen copper side of the exchange.
Funny enough by me the local government hospitals do actually answer the phones, and will even call you back as well, at least for me McCords and KGV hospitals. Oh and the Metro police emergency lines are more down than up, though to be fair that line often is answered, unlike SAPS where they never answer. to report the crimes you have to go to the police station, where you will get an OB number, then next day a SMS with CAS number, followed up later the day with the case being closed. Very efficient that.
Having set up call queues and ring all groups, it's great the phone rings, but the wetware still needs to actually answer.