What model router do you have?
Do you have an ethernet device or only wifi devices?
On the router, is the Internet light on?
What about the WLAN/2.4G/5G lights?
Some routers have a pushbutton to turn wifi on or off.
Was going to suggest factory reset but wanted to check config first which would need ethernet device.
If you press the WLAN button (middle button of 3 on rear edge of router), does the WLAN light go off?
Press again and light comes on. Any change with detecting wifi?
On the occasion you did the factory reset, did you have to re-enter your TPG username and password?
Looks like the wireless part of the router is faulty.
Out of interest, do your wifi devices detect networks in neighbouring houses?
If the WLAN light doesn't go off, sounds like router is broken.
When you did reset on router, it would have forgotten that your phone had connected in the past. So you would have had to connect manually. When you entered the wifi password, was there an error message or did it just appear to stop?
Not that it matters, but at the moment, do both networks show on your phones, or neither of them?
A moderator may not look at this post again. Tomorrow morning, you should make a new post with this extra info: the WLAN light won't turn off; whether or not the wifi network name shows on your wifi devices; that you can detect other networks.