Caller: They said they were the NBN

I've had at least one of these calls everyday, with different numbers. The last time was a different number but an automated number told me if I didn't switch to nbn my internet and phone would be disconnected and to press 1 to keep connected. So I did and told the woman I don't appreciate being threatened and she hung up. I tried calling the number back and telstra said it couldn't be connected. I went to the NBN website and looked under scams and they pretty much said to hang up if they say you are going to be disconnected. Clearly that would not happen, but some people might be sucked into it. I'm buying a sports whistle and next time they ring they'll cop an earful!