I had a similar issue with Hilton Garden In Mong Kok/HKG. I needed to check-out 1 day earlier. I called the property in advance and agent tried to amend the reservation but no success. A supervisor told me that early check-out was OK for this reservation and that the hotel would arrange for a refund of the HH points for the unused nights. Supervisor told me that notes would be in my reservation. At the end it worked out fine. No issues at early check-out and some days later I received a refund of the HH points.
I would call the property again and insist that hotel staff deal with it. Hilton Honors will not be able to help you.