The person who called identified herself as Grace Miller.  She said that they wanted to enhance our marketing effectiveness through Yellow Pages advertising.  I told her that we aren't interested, and she said "You don't understand.  Your company already has this listing, and we want to verify your information so that your advertising is more effective."  I refused to confirm any information with her and asked her not to call again.  Six hours later, she called again.  I told her that she had been asked not to call this number, and she replied, "I'm sorry, but this is the first time I have spoken with you."  I told her that I had personally spoken to her this morning and asked her not to call back.  Then, she hung up.