In the ACT, perhaps similar elsewhere, the Act has a provision that the Tribunal can give an order to give effect to a failed motion if opposition was unreasonable. Conversely it can declare a motion that passed to have failed if it was unreasonable for it to have passed. It decides the matter on what is known now and does not try to rule on whether any particular person was being unreasonable in voting as they did.
It could be that new facts have come to light so that the reasonable outcome would be different from what it was at the time the vote was taken. In effect, what you could ask of the Tribunal is for an administrative review.
If your vote being different would not have made any difference and there is no new information that might make others decide differently, then you probably just have to live with the OC’s decision. I would only go to the Tribunal or make representations to the committee to have them hold off until the matter is reconsidered if the decision would result in some serious injustice.