I called back the number (02) 6100 0663 but the phone just kept ringing

why can't this number be found by Telstra ?

Caller: Scammer

Called pretending to be from Telstra, said they will be sending someone to my premises to inspect the phone line... lol...

Caller: scammers

SCAMMER- Hello I am with Telstra. We will be providing NBN to your business. We would like to send somebody to your address.
ME- Hello I already have the NBN.
SCAMMER- Oh ok, by.

Caller: Claims to be Telstra

They say they're calling from Telstra to book times for managers to speak to us about NBN. Line is terrible, person I spoke to was barely understandable, hung up when I pointed out we had business concierge service and should not be getting calls like this.

Caller: Taxation office

Message says ring them back before the taxation department coms to get me for tax evasion

I answered with hello and caller said goodbye then hung up lol

Caller: claiming to be from Telstra

had thick Indian accent and I hung up.

Hung up when I answered. Called back and the number was not Valid.

Caller: Call Centre

Someone claiming to be from Telstra Business Service.

Two calls from this number today. Just hangs up when you answer it. Dont know who it is and dont care - just stop ringing me!!

Hung up when I answered

Hang up as soon as I answered

Robocall hangs up when answer