Caller: People o this ohone number stated they were from Telstra, But when I redialled this number0434 252 320, I was advised That Optus said this number was disconnected.

How can that be when a person, with an accent said it was Telstra and was my internet working Ok. when I sated yes it was ok They hung up. I rang back the number to ask why what was wrong. Yet the voice I got when I redialled stated That Optus a advised this number is not connected. Please advise ??