The easiest way to overturn a levy is to hold an extraordinary general meeting (EGM) which you can call by getting the signatures of 25 percent of owners, then get a simple majority of those at the meeting to vote to rescind the decision.
If you took this to NCAT you would either have to prove deceptive practices or that the majority of owners, properly informed, would have rejected it.
The easiest way to do that is to call the meeting and attach explanatory material to the agenda as well as lobbying owners in person or by mail. As an owner you are entitled to see the strata roll and copy the addresses of non-resident owners.
If that isn’t workable, I doubt if NCAT would step in, in any case, unless there was clear evidence of fraudulent behaviour.