Caller: I don't know, but supposedly someone to do with the NBN

I answered the call - a recorded message came on, a woman's voice, and saying something about Australian NBN, and how they are going to disconnect my service, and I can press 1 to talk to the technician. Of course, I didn't press 1, but hung up instead. I called Telstra about this, and was told that they can't do anything directly about scammers. I will not be answering ANY calls in future, unless I definitely know the phone number.