Caller: Telstra internet?

Received a call from this person calling me by someone else's name then stating that they're from Telstra Internet when I'm with Optus. No idea how they think I'm the person they claimed. Definitely not Telstra if they got my number wrong, but they obviously didn't sound like Telstra employees first thing they said was your Telstra IP address has a security issue which again I'm with Optus. Had to cut them off because they had the wrong person. Avoid!