Welcome to TPG Community!
In order to sign up for our ADSL2+ Off-net 200G, you need an active phone line. This phone line will be used for us to provide the internet service. If you have an active home phone from Telstra or other provider, that will do.
The Technicolor TG587n v3 which you received from Tesltra, should work given that you have been using it for ADSL2+. However, we need to make sure that the settings is not locked with Telstra. You can contact them for clarification.
The Technicolor TG789vac v2 HP which was given by My Republic is a VDSL modem. Since it will be using the same DSL line, then it is possible to work. We just need to make sure that the configuration of it is correct.
You don't need to purchase a new modem if your old modems are still working fine.
If you need assistance with your order, please call our Sales team at 13 14 23 (Opt. 1)