You can submit a formal complaint using the form available at http://www.auda.org.au/industrycomplaint/.
You will be required to be able to supply evidence that clearly shows that the domain name was meant to be registered in your details. The evidence could be an invoice or an email thread with the other party that explicitly displays the domain name in question.
Please also provide a time-line of your efforts to resolve your concern in the complaint details section and forward all relevant email correspondence (including headers) to email@example.com.
It is also important to provide evidence that you are the intended licence holder (registrant) of the domain name or are acting on behalf of the registrant. As such, we may require scanned copies of company, business certificates or related matter as well as potentially requiring photo identification of the owner or director.