My strategies with Phone Scammers:
Scammer: I'm calling about your electricity bill...
Me: Sorry, but we don't use electricity... (hangs up)
Next Scammer: I'm calling about your water bill...
Me: Sorry, but we don't drink water... (hangs up)
Next Scammer: This is Telstra calling about your Phone Bill..
Me (my favourite): Sorry, but we don't have a phone... (hangs up)