Several calls. Offering free (Govt. sponsored) electronic devices to monitor electricity usage. Not too pushy just called often
Failing that they offer shower heads. Have received these and light globes in the past which were good.

Caller: Australian Research Centre

Australian Research Centre wanting to do a survey on cost of living

Rang and did not leave message- assume spam

Called but refused to leave message. Blocked to be safe.

Hung up when there was nobody speaking. Assumed waiting to be connected to recorded message. How are they allowed to call when number is registered on “do not call” register.

Had a missed call from this number at 7 pm on a Friday night. Didn't leave a voicemail or message so I'm assuming it is spam.

Caller: Suspected nuisance caller

Called but left no message. I receive at least of these calls a day, so it is likely a nuisance call but unconfirmed.

No message left piss off malaka

Caller: Not sure

Called and did not leave a message
Like another reviewer, I saw that the number was attached to a permanently closed travel agent in Dandenong, Victoria, through Google Reviews. It is unclear who the person was calling me now.
Treating this as suspicious.

Google said it was a permanently closed business.
Number likely now a scam number. Called. No message left.

Rang and did not leave message

Dead air when I answered, assuming it was another of those robo-dial spam calls that was waiting to connect me with some sales person.