No message left, tried calling back number not in service.

No message left, could not call back.

Received a call from this number stating they were calling from my internet provider - I said I don't have an internet plan in my name.

He then said, I'm calling from your phone provider, which I replied "and that provider is" - he replied "Optus"

I said I'm not with Optus, to which he responded I'm a "big fat liar"