KRA (key result area) not filled....

I am working with a MNC company as an Executive. I am a member of registered Staff union. There is a policy of company to fill KRA for performance appraisal. But every year we finds that there is Inappropriate, Illegal and biased appraisal system conducted . We have also consistently quoted innumerable incidents of discrimination, and unfairness while conducting the Appraisal procedures. We have objected to the violation of the course of action of appraisal system Conducted. We have raised this issue innumerable times with the HR Manager. But no reply given from management. In spite of the same they are illegally pressurizing us to fill in the KRA forms. Also management issued to letters to all not filling KRA members stating to take action and no increment to all the members. Dear Experrts pls guide me can management stop increment of all the members who not filled the kra and what action can they take against this. Our union also given reply to the letters why we are not filling kra.In majority cases KRA was forwarded for further processing without discussion (Gross violation of Company guidelines ) No performance related discussions after Ratings to explain how ratings were arrived at . (Gross violation of Company guidelines ) In 2017 deliberate attempts have been made by the Functional Manager to give a lower rating than what is deserved to many of our staff. This unwelcome conduct of the Functional Manager amounts to harassment at workplace. Pls help