Caller: "The Australian Broad Band Network"

SCAM - A woman's stern voice stating "This is a call from the Australian National Broad Band Network. We have been trying to get in touch with you, however we are going to disconnect your landline and internet connection within 24 hours as the NBN services are now available in your locality, so for uninterrupted services please press one to get yourself connected to our technician."
We are already on the NBN as are most Australians. Furthermore it's your ISP (internet service provider eg Internode) that deals with these matters. The NBN deal with your ISP, not you directly.