[Mashiro]

What exactly do you mean with "air time"? It's 2G and 4G by the way.

The government of SA is sending you messages via WhatsApp or text messages? If you get text messages from them then they probably let it be sent at carrier level as a "broadcast" message. So basically everyone in the network gets the message. You could try to block the number that sends the SMS if it is always the same. If they send you messages over WhatsApp I think you can also block the number/contact.

Anyway. About tracking. Even if you change back to an older phone you can be still tracked via silent messages or cell tower triangulation tracking which by the way can be pretty accurate in terms of tracking of your position. Cell tower triangulation tracking can be as exact as a few meters difference to the real location. And silent messages are messages sent to your phone that you don't even know about. No notification, they don't show up on the phone or anything else. The silent message also known as silent SMS or stealth ping is used to activate the tracking procedure. It bascially helps to trace/track the number.

https://cellphonetrackers.org/mobile-gsm...tions.html
https://edri.org/edrigramnumber10-2silen...-suspects/
https://github.com/CellularPrivacy/Andro...silent-sms