Hi
We do not support 3rd party products but I see no reason why that range extender would not work as long as the Wifi on your TPG supplied modem is working. If you can connect other devices Wirelessly to the TPG modem then Wifi is working.
You should contact Netgear for support for your product.
This link may give you more information also.
https://www.netgear.com.au/home/products/networking/wifi-range-extenders/EX6100.aspx
Regards,
Peter
