TPG NBN not fixed

Level 1c
After nearly 12 mths of faultless service.... boom.... 2 weeks ago 4/4/20,during heavy rain and wind, our tpg nbn stopped working, and it is still not working, despite claims to the contrary.
For the most part during this time all correct lights are on nbn box and modem/router. I have reset both multiple times, connected to modem via ethernet cable and replaced the ethernet cable between the 2 boxes..... no improvement. All this while failing to get any tech support.
Since first failing, our access has been quite variable. There have been brief periods where speed testing and function appear perfect, but not for long enough to stream a single show, play a game, or reliably access my work before completely failing. Mostly there has been poor and unstable access if any.
Eventually on 13/4, I was able to contact online help. Despite initial testing indicating stable normal function, eventually it was suggested there was a line problem and it would get sent up to nbn or engineers.
Since then I have had a few sms and 1 phone call advising me that it was working normally and my ticket would be or had been closed, despite clearly not functioning properly (if at all) at my end.
At this moment, despite all lights correctly on, I cannot even get enough connection to run a speed test. It has now been 2 weeks since this started, and I am not confident I am being taken seriously or that the problem is being properly looked into so it can be fixed.
The children need to access school remotely, and there is work I need to be able to do from home, including urgent health services in 2 days time.
My ticket no is 10418708. Can someone please actually get this fixed

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Level 1c
Thanks for your follow up Peter.
Nbn tech visited yesterday, no surprise to hear there's a network problem affecting numerous properties in the street. Awaiting news on when that might be resolved.
Unfortunately since last evening things are worse. No connection at all, not even the patchy connection that was enough for the kids to get through their schoolwork.
Level 1c
It is now 1 month since this started. NBNco have come out 3 times, and I can only assume nobody knows what the problem is or how to fix it.
First visit, tech checked out everything on our property and determined a network problem- no argument with that theory. Became aware of neighbours with different ISPs also having problems.
Second appointment, 2 vans, techs worked out on street. Problem seemed to be solved for 2 days, until it started raining again. My biggest complaint about this appointment was the requirement that I be home for 4hrs even tho nobody entered my property or even contacted me to advise of their visit.
Third visit 2 days ago, another tech changed the nbn box, claiming it was damaged on the inside. He required me to state in writing that my internet was working, even though it was clearly not working properly based on my speed tests over last month, and would not listen, blaming TPG for any remaining problems.
Surprise, surprise.... 1-2 hours after he left it wasn't working at all again.
So, after 1 month and 3 nbn visits NOTHING HAS CHANGED.
We have limited intermittent access. The kids can't do their remote schooling properly and I an unable to access work to keep up with my responsibilities. We are unable to access streaming TV or xbox services.
How do i complain about nbn handling of the situation?