Send them a bill for the amount with a reasonable time for them to respond. If they fail to do so, take them to NCAT where, at the time of writing, the Tribunal can award compensation.
I say “at the time of writing” because, according to this report by strata lawyers J S Mueller, this has changed over the years and could change again.
However, if you were the unfortunate test case that forced another backflip at the tribunal, you could always go to your small claims court.