In NSW the quorum for an AGM is one quarter of the votes either in person or by proxy, in raw numbers or by the total of the Unit Entitlements.
So if the proxies were legitimate (provided on the correct documents) and everybody was up to date with their levies then this was well within the quorum limits and the meeting was legal. This is what the Act says:
There is a quorum for considering and voting on such a motion or at such an election only if:
(a) at least one-quarter of the number of persons entitled to vote on the motion or at the election is present, either personally or by duly appointed proxy, or
(b) at least one-quarter of the aggregate unit entitlement of the strata scheme is represented by the persons who are present and entitled to vote on the motion or at the election, either personally or by duly appointed proxy.