I had the same automated message from (03) 2134 9761 and (03) 2311 7211 and both have been reported also.

Caller: "NBN" - Not actually them

Automated call saying they are from NBNCo and they are going to disconnect services in 24 hours and to press 1 to get connected to technician.

Basically trying to scare people in to signing up to their internet plans, but won't admit what actual company they are. Pressed them on the issue, as NBNCo are wholesalers only, but got hung up on.