I recall having an issue with this a few years back. My last character on my WOH account is the letter O. Double check that, just on the off chance that is an issue. More than once I supplanted the O for the number zero. But I also had an issue where I had two WOH accounts, and I did not know it (they merged them). It was a pain when I first did this, but seamless after. Try contacting Hyatt too. They do have a department--non customer facing--that works on this. Not sure if they can assist on this specific issue, but they may be able to help.