Embrace cold calls. Engage them in conversation. They'll get fed up before you do. It's both not earning and costing them money. The best ones are the internet cut-offs and computer virus calls. Act as though you believe all they say with plenty of 'Oh dear' and 'That's terrible'. Act the complete computer div. Just use your imagination. It actually becomes quite additive. Our other way, every Thursday we look after our two year old grandson, is to give the phone to him. He just jabbers on until they hang up.