Who is a higher authority than mall security guards and their supervisor?

I'm just wondering who I can complain to about mall security guards in westfield belconnen in Canberra. Yesterday, I felt they discriminated against me. What happened was I lost my temper with a couple of idiot strangers who were annoying me and I yelled at them with course language and they also told me that they got reports that I was being abusive to lots of people (plus myer staff) and one report said that I yelled at a woman and her baby and was behaving in a threatning manner to all of them. So, I signed a piece of paper (a contract) stating that I will be banned until the 10th of September, 2011 (a 3 month) period which I think is absolutely stupid and unfair!!!!!!!!!!!!!!!!!!! :( They took down my details from my driver's license and took too mug shots of me (I hate the flash on those cameras. There was a red flash and then a white flash and they both dazzled me. Idiots!!!!!!!!!!!!!!!!!). Anyway, the guy who was in charge of them (Rob was his name) was somewhat rough and he had a supervisor!!! So he wasn't really even in charge. My question is: Can I complain and take action against them to a higher authority?? I'm thinking of going back tomorrow and doing this. Even though they told me that I would be trespassing. But it's just so unfair. Can you please help me out here!! Thank you so much Everyone!!!!! :)