Caller: I don't know.

I got a call from this number. I answered they hung up on me. I then called back to get a auto message saying if you want these calls to stop to email... (I dont know they said it too fast and only once.) I have blocked this number until I can verify from AI that it is one of their numbers.

I returned a call from (02) 8366 2567 but the voicemail didn't mention the company name

Answer the phone, muffled voices and then hung up. Tried calling back but answere by a machine so hung up.
The number tried calling me again but hung up on me after a few seconds.

Caller: APM Employment Services

This number is from APM Employment Services

Caller: Amnesty International

Perhaps these numbers change, so I'm not sure if this was, or will once again be a scam - but I called back, this was from Amnesty International doing an education/donation campaign.
That said, as they were asking for donations, if that's not something you're interested in it might seem like a pain to talk to, but I didn't pay and I found it an informative conversation.