I had the same thing happen yesterday (1-24-09). A very persistent person from EZ1Rate. I told him I wasn't interested. It was obvious where this while thing was going, but he wouldn't get off the phone and was getting very argumentative. So . . . I hung up on him.
Minutes later the same person called and asked why I had hung up. I told him, again, that I was not interested and asked him if he understood the concept of "no free lunch." That's when he told me I could have the $300 in coupons good at any gas station with no expiration date.
I hung up on him again and, thankfully, he has not called back.