I had a Hilton do this a while back. I only found out about it when I went to access the lounge (across the hall, so convenient) and my card did not work. I was meeting friends for dinner and mentioned on the way out and they tried saying no, I wasn't entitled to access. I objected but went on to dinner. When I returned to my room there was a letter and new keys on the desk saying I was correct and was granted access. I am used to knowing more about the program rules than many of the FDCs, but since they don't get much time to be a member I'm not surprised and deal with it.

If the property refuses to budge you can escalate the issue with HH and hope you get someone that will raise the issue with the property or pass it along to their HH coordinator. It may not help with your visit, but correct their behaviour for the next guest or you next visit.