Cali... it may be time to let them know you're serious.

Personally I would simply contact a property contract lawyer and have them write a letter of request to the association asking for the person(s) contact information of who has been filing the complaints. Then I would have the lawyer type up a nice letter to both the association and the persons involved in the complaints to remind them that harrasment is a valid charge and can carry jailtime.

If they don't back down, I know some much better, less legal ways to make their life hell... just ask...