Caller: No idea

They called about 15 times today on this and another number ending in 2000, immediately followed up with a private number. I answered all three with this exact script and didn't hear from them again after that:
"You have reached the call centre for the Australian Federal Police. Your IP address has been noted. Your phone number has been noted. Please press 1 to continue."
*click*
Hehe

Caller: Kogan Customer Support

Called about an issue I had with a product that I purchased and reported to them online.

when I answered the line was disconnected

Caller: no idea

came through on my phone as 0011111000. No idea who it was, they didn't leave a message.

Caller: Family member overseas

I've had several missed calls from this number in the last several weeks.
The Telstra SMS messages following the calls indicated no message left and because of the strange number and lack of messages I assume the calls were dodgy.
Today I had another missed call but the Telstra missed call message text indicated it was from my brother in the US.
I called him on his mobile and he confirmed that he had left the message and had been trying to get in touch with me but had not left any messages in his previous attempts.
Why the calls were showing as coming from this number is a mystery.
My advice to anyone receiving a call from a strange number like this is to leave it unanswered and see if the caller is willing to leave a message identifying themself and the purpose of the call.
As a rule I would not call back a missed call number without knowing who I'm calling.

Caller: 011111000

spammed me multiple times.. I called number back and "number disconnected".

Called 7 times maybe a dental health service from New Zealand with branches in Australia. Severely p.....d off as its bed time

Caller: No idea, didn’t answer

Ignored the call, no message left of course.