Originally Posted by
edthomas
The Guanratee is bogus. Hilton will not honor the Best Rate Guarantee when their own site lowers the cost. I paid the advance price, saw that the hotel lowered the rate and filed a claim which they would not honor. Never pay a non-refundable rate to Hilton assuming they will "cover" your if they lower their own prices let alone a third-party. It's a game you can't win (Call me Bogus Claim Case 7588325)
Welcome to FT
edthomas 
I [just about] agree with you that it's "A game you can't win". They make it hard.
Anyway, your situation is excluded from the "best rate guarantee" since you are comparing a Hilton Family booking channel rate with a [later] Hilton Family booking channel rate.
This "Guarantee" only relates to publicly available rates
on non-Hilton Family booking channels (except for "opaque" websites) when compared with the rate of an existing Hilton Family channel booking.
The T&C were most recently listed by
DaddyRabbit in post
#802 of this thread.
NB. Even without this non Hilton family booking channel exclusion you may have also been ineligible if the reduced rate became apparent more than a day after the initial booking due to the "within twenty-four (24) hours of booking your reservation" clause.