alinka – if your Strata Manager is not the Licensee of the business, then make an appointment to see whoever it is that holds that position and make your complaint.
Depending upon how that goes, the peak professional body for Strata Managers is Strata Community Australia (NSW), so start with a call to them on (02) 9492 8200 in order to find out if your Strata Manager or their Licensee is a Member, and if either is, then have a read through the Code of Ethics and if what you allege that your Strata Manager is doing is contrary to any provision of that, then lodge a Complaint using the Form supplied with the Code.
As a last resort, contact the NSW Department of Fair Trading who’s responsible for the Property Stock and Business Agents Act under which the conduct of all Strata Managers is regulated; just don’t expect too much action as I’ve in the past found the Department to be largely impotent in investigating such matters.