Caller: Charity

They hung up when I answered & then it went to voicemail when I called back, telling me they were a charity, although didn't name which one.

It’s a service using a fake number. When u call them back there is a recorded message which tries to get you to email them to stop the calls. I imagine as a way of confirming your mobile and email address details and what further I am not sure. Most likely a scam

Phone warned it was spam

This number calls constantly, a few times per day. Blocked

Caller: Amnesty International

Amnesty International. Calling to collect information, didn't get into call far enough to see if they try and sign you up.

Disconnected when call returned

I returned a call from 0491 695 581 but reached vm for Smart Health Australia