Depending on your evidence you can file with NCAT without a lawyer, especially as mediation didn’t resolve the issue.
We did, OC had lawyers (whom I wont name) charged owners a small fortune, but we won. The same lawyers are now earning good fees from the Strata Manager trying to reverse the licence cancellation by Fair Trading,
You need to get in contact with as many owners as possible to gain their support, so if/when the OC puts a motion forward to approve lawyers it gets voted down, then you are on a level playing field and if the basis for your claim is valid the tribunal will generally do the right thing.
Happy if you send me PM to give you some advice off line.