Caller: He said he was from Telstra but he wasn't

He wasn't from Telstra because they have to identify themselves by saying their name, that they're calling from Telstra and that the call is being recorded. He didn't. I asked him to take me off their database as I'm on the Do Not Call Register. He became very rude. If he was from Telstra he would not have been calling from a mobile number, he would have had to say his name and he would have had to say the call is being recorded. I immediately called the number back and it said it was disconnected. It was a scam. I used to train call centre staff in Telstra so I know their rules very well. I would guess that they have spoofed someone's number.