But if the only way they could contact you was through the specific "want ad" that you posted, wouldn't that help some? You're not asking them to come to you, you're asking them to reply to that ad. They shouldn't need to know anything else about you except what you posted in the ad. This assumes that the Broadcast Shopping company that is acting as the mediator between you and the sellers isn't going to sell your contact information, but that should be made very clear, "Hey, the only way a seller can contact you is through this one ad, and you can turn the ad off as soon as you get the offer you're looking for".