Assuming the number displayed is accurate and not spoofed. Someone claiming to be from ANZ Cyber Security and wanting to confirm a suspicious transaction. I don't bank with ANZ & when I asked them to identify themselves, they hung up.

I think this is a spoofed number to make us think they are in Adelaide. Calling 4 or 5 times a day. When I answer, they don't speak (possible delay) so I believe they are calling from a dodgy overseas call centre.