Called number back- market research company that says it complies with the do not call register as genuine research- gives times that it will call and lists regulations

Persistent caller to a mobile number only shared with a handful of family and close friends. Probably a robot working through the entire range of mobile numbers allocated to Australian telcos.
I only take calls from my contacts. Everything else is ignored and I never activate voicemail/message bank on a mobile.
Just like the good old days when the phone was bolted to a wall in the kitchen or entrance hall, if I pick up you can talk. If I don't, too bad ... I'm out where no one can bother me. :)
As a society we sabotaged our collective peace of mind by making ourselves available 24/7 to every Tom, d*ck and Harriet who has a mind to call our private telephone number; worse than having religious fanatics knock on your door while you're trying to watch the big game on a Saturday arvo.
Time we taught all the scammers and flimflam artists that "No means 'No'" ;).

Called me 3 days in a row - no messages left - blocked

Spammer. Calls in the evening and never leaves a message. Blocked.

Scam caller who did not leave a message .

I don't know it a scan

Another caller who did not leave a message SCAMMER

Voice recording phishing scam

Did not leave a message