Hello Ms. Sima,
Your case in quite interesting. List down the various issues, which in your opinion, is not correct from the statutory point of view and also ethically not justifiable. You haven't yet disclosed the name of your organization or rather the segment that your company is in to and the location of your factory/organization. Further you also have not mentioned the total number of your workforce (both the blue collars in the shopfloor and the white collar office staff). A critical evaluation can be done only after your have all these data with you. Also look into the company's performance for the last 5 years in terms of overall turnover and the bottomline revenue.
Resorting to union or creating pressure on the management indirectly are the tactics to be used as a last option, because, once you start indulging in these activities, you lose your focus on real time action which, you as HR need to do to bring the situation under control.
If most of these issues are a result of ignorance of the top management, then ofcource, you can definitely work your way out. Otherwise, it's better to gracefully quit and look for a different employer who is professional.