Nads,
I couldn’t tell from your post as to whether you were an owner or tenant, however:
If you are an owner, there is no law preventing the manager from passing on contact details. you can also book a time to view the Owners Corporations records with the manager. The information must be readily available to members.
If you are a tenant, I could understand the managers reluctance to provide details, however you can carry out a title search (small fee) through your states online land registry. this may not provide contact details but definitely name on title and notice address.
Hope this helps.