I always answer calls in a different time, like an old woman from numbers I don't recognise, and if they answer I'll continue until i feel comfortable to talk in my own time in case they are recording my voice for yes and other words they use for scamming people on accounts etc. I answer they hang up, so obviously a fake number wanting to know if my number was a number that is active.

I called back number 0488 849 236 rang once then goes to busy tone.

Calls me 3-4 times a day, when i pick up the phone hangs up straight away.

Seems like scam. Goes straight to a voice message.