I did not return call because they did not leave a message on answering service. My rule for calls from numbers I am unfamiliar with is simple - IF THEY CAN'T LEAVE A MESSAGE, IT COULD BE A SCAM.

No. This Call Centre Is Based In WA With A Sydney Extention.
The Number Is IINET Internet Callback. It's All Good. No Telemarketers!

I don't think it's legitimate if AAPT are making multiple "return" calls to people who aren't with them. To me, that seems to fall under cold-calling telemarketing.

The number AAPT uses to reply to Customer enquiries

Nothing wrong with that.

Your call type question does not cover this type of legitimate call

AAPT

I am overseas at the moment with my Australian Cell phone and I had 7 missed calls from this number.  Thank god I didnt answer them or it would have cost me a fortune.  Absolute nuisances.

This number is AAPT

This is AAPT's offshore call centre (Phillipines) returning a call to you.

to many pranks