Not sure about verbal abuse... I try to stay polite however annoying they might be.

I've tried to countersell stuff, just for fun. "listen, glad you called, coincidentally I have this great 6 yr old laptop, which you might be interested in. It's only £239.99. What do you think? I accept paypal..."

Once I got transfered to a "team lead", who prommised to think about it and call back. He never did...