In my opinion your Committee are acting unlawfully.
The Committee does not have the authority to authorise a Special Levy. Special levies must be authorised at a General Meeting.
Special levies of up to twice the amount of an Owners Corporation’s current annual fees can be raised by ordinary resolution. Special levies higher than that can be raised by special resolution.
OWNERS CORPORATIONS ACT 2006 – SECT 24
Extraordinary fees
(1) An owners corporation may levy special fees and charges designed to cover extraordinary items of expenditure.
S. 24(2) substituted by No. 78/2013 s. 4.
(2) Subject to subsection (2A), the fees must be based on lot liability.
S. 24(2A) inserted by No. 78/2013 s. 4.
(2A) Fees for extraordinary items of expenditure relating to repairs, maintenance or other works that are undertaken wholly or substantially for the benefit of some or one, but not all, of the lots affected by the owners corporation must be levied on the basis that the lot owner of the lot that benefits more pays more.
(3) The owners corporation may determine the times for payment of the special fees and charges.
(4) A special resolution is required when exercising a power under subsection (1) if the amount involved is more than twice the total amount of the current annual fees set under section 23.
(5) Subsection (4) does not apply if the fees are levied to pay for or recoup the cost of repairs or maintenance carried out to any part of the property for which the owners corporation is responsible where immediate expenditure is or was necessary to ensure safety or to prevent significant loss or damage to persons or property.
My advice is for you to seek legal advice ASAP and then take this issue to VCAT. If you can encourage other owners to join with you then that would obviously offset the costs.
This issue is far too complicated for you to fight on your own.
Ask for costs to be awarded to cover your legal costs if you win.