If you believe a security guard has used excessive force against you, this could constitute an unlawful assault. You can report the matter to the Police.
If you think you were unlawfully refused entry to a premise because of your age, race, or sex, you can make a complaint to the Equal Opportunity Commission. However, such allegations can be difficult to prove.
If you think you are being victimised by a security guard, you can complain to the owner or manager of the property or the security firm where he or she is employed.