William, thank you for trying to help, but unfortunately your idea didn't work. I sent that email explaining the problem, but in their reply they told me to call 1-800-297-7327, which is a number for Amex (but not the number on the back of the card). The first thing the automated system at Amex asked for was for me to enter the card number, but when I did, it said "Thank you for calling American Express, goodbye" and hung up. Any idea how to get someone at Hilton interested in the problem?