Caller: Scam call real number?

This is scary,. Now either the scammers have been able to mirror this number or something else is happening. The were calling about my NBN having problems. That I will have noticed. I said no it was working fine. They hung up. This is the 2nd such phonecall I have received within a month. Last time they didn't hang up, but spoke to me like I was an idiot and didn't understand computers and actually tried to use yelling and fear.