Get online support
Hi @Lulu86 . Have a look at this.
https://community.tpg.com.au/t5/Home-Phone-Voice/Call-Diversion/m-p/4503/highlight/true#M208
In this description, it says TPG such and such. In yours, it will say NBN such and such. It's in the control panel. Just delete the diversion number.
If you want Call Waiting disabled, that can't be done online. Just make a new thread with that request.