Abuse is a crime. The appropriate people to deal with a crime are the police. If you - or anyone you know - have been abused, please contact the police. Alternatively, you can contact the Safeguarding and Ministerial Integrity Office at firstname.lastname@example.org or call (02) 9390 5810.
You may also want to speak to your Parish Priest who will be able to provide support and guidance. The Archdiocese has a legal obligation to report crimes to the police.