Was the meeting quorate – were one quarter of the owners represented in person or by proxy, either in simple numbers or as a total of unit entitlements?
If a meeting has been called properly and the chair doen’t show, provided the meeting is quorate you can choose someone elese to run the meeting.
Even if it isn’t, an order to overturn a decision at a meeting can be rejected by an NCAT adjudicator on the grounds that no injustice has occurred and no one has suffered as a consequence. I’d say you’re pretty safe.
By the way, I hope you didn’t re-elect the shair. What kind of chairperson doesn’t turn up at an AGM?