Are you referring to the building facilities manager or the strata managing agent? Either way, they are incompetent fools, backing up SCA President Julie McLean’s assertion that there are too many untrained and unqualified amateurs passing themselves off as strata managers in Victoria.
Find out how much it would cost to rectify the situation to your satisfaction and then bill the OC managers accordingly.
By the way, I doubt if the “precedent” would stand up in a tribunal. It was a decision the manager was not empowered to make (I’m guessing) so it can’t be used to justify any other decisions. Might also be worth asking what relationship the manager has with window installers.