I don't get those calls in the Phils, maybe because I never answer the phone ;-)
I do get on my Swedish line though (VoIP phone). If I have nothing better to do I take my time to talk to them. Ask questions. Drag out the call as far as I can. They get all exited when they realise they are about to make a sale. When they come to the selling part I'm very interested in getting their product. When they ask for the my address and I give up my Santander address they gets very sad and quiet. Some even angry because I didn't tell them in advance, but wasted 30 min of their time. Well, I enjoy it every time.