I received a call from this number 0409 955 774 which I didn't answer. But I didn't call back until over 3 hours later so the caller wouldn't expect a call back. The phone went to an answering machine with a woman saying to leave a message she will call back and I hung up. Sometime soon after, she returned the call. When I answered she didn't speak and kept quiet. After about 8 seconds I said "Allo?" She replied: "I'm returning this call, you called my number." I said "YOU called my number earlier I returned your call." With a rude voice she said "I don't think so." And hung up.
What I did is send her a text imessage immediately hilighting her number and what time she called with the message: " You don't think so?" It ended there of course. Be careful, when you suspect one of these scammers, don't just let it go to your messagebank. They get paid for every call that gets connected. So if you suspect the call, just hang the call, don't answer or let them go to your message bank as that's considered an answered call. They get paid for it.