heh heh, they've been calling random numbers in oz for a while now.
They've called us on a few occasions.
My best so far is keeping them going for half an hour, in the end I had to get back to the study and I told him he didn't know what he was talking about and that I knew it was a scam and wished him luck on his next call.
UNfortunately it must be worth their while to keep doing it otherwise they wouldn't have the funds to keep going so they must be getting a few less literate people in. So warnings are always warranted to people who dont know any better or people who might know someone who doesnt know any better.