Harassment at work & bullying basis sexual orientation

I was harassed and bullied by my manager over of period of many months, I reported it to the management and took it to global level. They investigated and testified many other employees who faced same harassment by same manager. They changed my reporting manager but did not take any action against her. They are saying that they have given her a written warning. They had already given her verbal warning earlier many months ago when other employees had reported agaisnt her. She has written my this years report clearly saying I am not competent for the job and I should be fired. Now after this investigation its clear that this is her false and fraud attempt to get me fired then why cant they take some strong actions against her. Kindly assist me in this and let me know if there is some legal course of action or legal terminology that I should use in writing to the top management that this is not accepted and I need justice. Also to tell you the company has zero-tolerance policy.