It depends what you want. If you simply want the strata manager’s behaviour to be reported, compile your evidence and send it to Fair Trading (there is an online complaint form). If it’s really, really unforgivably bad, someone from Fair Trading will call them up and tell them they’ve been naughty and ask them (nicely) not to do it again.
If the strata manager’s action were unprofessional, dishonest, outside the scope of their contract and have cost you financially (or otherwise), and you can prove it, take your evidence to a strata lawyer and ask them what they think your chances of getting compensation might be.
However, bear in mind that no strata manager in the history of NSW strata has ever been “struck off” or penalised in a meaningful way, just for being really crap at their job. Fraudulent behaviour is another matter entirely and you should talk to a strata lawyer if you think you have a case.