Thanks for your query.
If you are going to use a third party modem/router for your TPG NBN HFC service, the bundled VoIP will not work as the settings are embedded in the firmware of the supplied modem/router.
You'll be able to use a third party device as long as they are compatible with NBN technology, can be configured as PPPoE with your TPG username and password and can change the VLAN ID tagging to "2".
If the given device can accomplish the required field, then it will work with your service. You may contact Netgear support for further information.
If the supplied TP-Link modem/router is new, then it is still within the 12 Month warranty. Please send me a PM with your TPG username or customer ID number to check this further.