Caller: purported to be from Australian Broadband Network

Up to six calls a day over the last month saying that my phone and broadband are being disconnected as the NBN is now available in my area (recorded message) I have been on NBN for over a year. They appear to be able to harass people to their heart's content without redress but if I succumb to the extreme frustration they cause and threaten them the I would be the criminal. What a great country to live in.