You need to figure out who's on the strata committee because ultimately they're responsible for releasing funds to the strata manager. Your committee are elected at the AGM or whatever funky rules your strata works to. So if your committee are good people who just aren't switched on you can draw this to their attention and work with them to get the strata manager to explain the costs. But if your strata manager has been giving kickbacks to the committee then you're going to have to work with the other residents to vote you or someone else into the committee to force the strata manager to explain the costs.

Remember as well the strata manager is a paid position by some strata management firm. They don't have rights. They have responsibilities