Same thing happened to me at the Midland, TX hilton about a year ago. Front Desk clerk told me it was the LAST room. Turns out when talking to the manager the next morning there were other rooms, she just didn't want to upgrade me because my rate was too low, even though I was at the time Gold VIP. Anyway, I talked to the manager, and also talked to the Regional Manager for Hilton after I didn't feel it was well resolved. I was given a CRAPLOAD of HHonors points and learned later that the lady was fired for lying. Just keep going up the chain of command...