The following is offered as useful wording, sentiments and ideas for answering enquiries from members of the public.

(1) Opening Sentence

Thank you for taking the time to write to the APF.

(2) Who APF Is

A BIT FORMAL:

APF is all-volunteer organisation.  It conducts research into privacy matters and makes submissions to parliaments, government agencies and private sector organisations, seeking better privacy protections.

LESS FORMAL:

We're a privacy advocacy organisation, but we're entirely voluntary, so we have to focus on broad policy issues and can't tackle specifics.

LESS FORMAL AGAIN:

In general, we don't have the resources to assist with specific complaints.

But this is a matter of serious concern, and behaviour like this needs to be nipped in the bud.

REALLY, REALLY INFORMAL:

IANAL (I Am Not A Lawyer) and this isn't advice, because I'm not capable of giving it.  But I'd have thought that ...

(3) What To Do First

Your first step should be to raise the matter with the organisation that's causing the problem - and you're clearly capable of writing an explanation of your concerns.

(4) Where To Go Next

The Commonwealth Privacy Commissioner covers both the federal public sector and the private sector, and there are Commissioners in three States and both Territories.  They have an obligation to provide advice, and to handle complaints.  The Commissioners' can be found here:
http://www.privacy.org.au/Resources/POA.html

Generally, Commissioners expect a complainant to have already approached the organisation concerned. 

(5) Closing Words

We'd be pleased if you'd keep us up-to-date with progress in the matter.

(6) Signature

Sign as your own name, your function (e.g. Board-member), of APF