Welcome to the Community!
We were able to locate your account using your community details and tested the line, but was not able to detect any fault.
The WiFi connection is prone to signal interference, which may have caused the issues.
We've created some articles that will help you improve your home network. Refer to these articles:
If you really want to use a third party modem/router, please note that the bundled VoIP will not work with it.
If that's okay, then you need to get a VDSL modem and the VLAN ID needs to be configured to 2.
Any VDSL modem/router should work with the TPG NBN FTTN service as long as the VLAN ID can be changed to 2.
Let us know if you need further assistance.