Mental harassment at work

Hello, I work for a firm in gurgaon. We had a agrument in our as one of the teammate who had more experience than us would always try to point out mistakes in our work even if there werent any, she would shout at us. She would always maintain distance from us And would always complain about us to the team lead as well as manager that we were misbehaving with her and were ignoring her. Our manager always supported her and told us that we were wrong and then he decided to merge our team with another team. And all the lead responsibility were handed to the other teams leader. He also supported her and only took sides with her and his team and completing ingnoring me and my other three team members. His team would always misbehave with us and they looked down on us. make us do unnecessary changes in our work even if that was not atall recquired.We were always burdened with heavy work load while his team was free most off the time. He would always appretiate his team members in front of the manager and nver talk about us. He would try to point out mistakes in our work all the time so that he could report it to the manager. We were never appriciated for our work. And when we complaint about it to them, they always said that they appreciated us. Whenver there were new project coming in the team the teamlead would assign those to his team and that girl, we were never included in anything. One of my team mate got angry because of his biased behabiour and complained it to the manager. Instead of taking action against it the manager moved that girl to another team. We felt really ingnored and mentally tortured. One of my teammate resigned cause she was not able to handle the pressure. Now the two of us were left. We openly confornted the team lead about his behaviour and he promised that he would change. But he never did, instead the responsibility i had in the team were taken away from me without any reason. All this stress from the office lead to medical issues for me. So we both resigned asking to be releaved early. and after alot of struggle my teammate was releaved in one month. Recently the seperation policy was revised an notice period was increased from 2 months to 3 months. And we had resigned after this policy change I had asked them that i would serve 2 months. However the manager never called me for a discussion regarding my resignation. And after a month i was informed that i would have to serve 3 months notice period. Whenever i went to my manager for discussion he would ignore me and say he would not agree. So i went to the HR and informed them about my medical condition, but even the HR lady was not ready to listen she said the same thing. So i went to the HR head. He said he'll set up a meeting with my team lead and manger and HR and he would also be present there.But he never came to the meeting, and instead of discussing about my releaving the Teamlead and HR were trying to prove me wrong in every aspect. The HR was trying to make me agree with her, but when i didnt she misbehaved with me. Now what sould i do. I really cant handle all this stress.