Assuming you are in NSW, the Act here says this:
(2) Contributions levied by an owners corporation must be levied in respect of each lot and are payable (subject to this section and section 82) by the owners in shares proportional to the unit entitlements of their respective lots.
Then, you can apply for orders under this section:
(1) The Tribunal may, on application, make either or both of the following orders if the Tribunal considers that any amount levied or proposed to be levied by way of contributions is inadequate or excessive or that the manner of payment of contributions is unreasonable:
(a) an order for payment of contributions of a different amount,
(b) an order for payment of contributions in a different manner.
(2) An application for an order may be made by the lessor of a leasehold strata scheme, an owners corporation, an owner or a mortgagee in possession.
If a contribution that is the subject of an order by the Tribunal under this Division has been wholly or partly paid:
(a) an order to pay more has effect as if the owners corporation had decided to levy a contribution equal to the difference, and
(b) an order to pay less imposes a duty on the owners corporation to refund the difference.
And finally, you can seek a reallocation of the unit entitlements under this section (click here).
However, if you are in WA as your name suggests, a completely different set of laws apply but they may have the same effect.