OK so this got a much quicker reply, but they still didn't really read my original e-mail, and thought I was talking about a different stay.
When I pointed out the stay I was referring to, they just asked me to send in a scan of the invoice, even though the stay already appears in my HHonors activity.
Sigh...
i haven't had much luck with either the Syd HHonors address or the diamond one. Still chasing qantas points from a stay in September. Sydhhonors just stopped replying and the diamond email address told me that qantas had given me the points. Qantas have agreed with me that they haven't so am still waiting for diamond to get back to me with a copy of the invoice...five days and no response. Am going to keep hounding them now just on principle...