The home owner's association does not have any keys for the mailboxes.
You will need to replace the lock for the mailbox.
New locks can be obtained at McLendon's Hardware.
In order to remove the old lock, you should either meet the mail carrier at your mailbox when they are there to deliver mail or to contact the post office at 4301 NE 4th Street, in Renton at 425-227-6304 to arrange a meeting at your mailbox.
Once they open the mailbox, you can remove the old lock and take it to McLendon's for a replacement.