Being retaliated against due to sexual harassment claim

A few months ago I went to HR to discuss a situation with a co worker for sexual harassment. After they talked to the employee he went around telling my coworkers to watch themselves because I was after everyone's job. I was treated like I had the plaque by coworkers and managment. I asked HR to have a discuss with him and I. He refused and said he will only speak with me when HR is present. Then he doesn't show up to the meetings. We switched seats so he was on the other side of the office. About 2 weeks ago they promoted him to management. I traveled the week after that. So when I came back I went to my manager and asked how this will work with he and I since he works with my accounts. I was told that they have to protect him from false accusations from me. So he will have other managers present at all time when dealing with me. That was Monday and by Thursday mid morning I was requested to see management in the afternoon. When I got to her office she had HR as well and I was written up for being for being "negative". I was told this is all stemming from the last 2 weeks. I travel for work and was out the week after the announcement of his new position which was on a Friday. I was barely in this week as I had Dr appts for my kids. When I was in the office I was at my desk working on so many projects I barely talked to anyone. When I asked for specifics she couldn't even provide them except to say everyone is coming to her and other management saying the same things from two of our office building. " I was told this is what you did to him and how do you think he felt. " All the accusations basically stemmed around him and two of the managers. When I asked HR who was in the room to confirm what was discussed in our meeting months prior she agreed with me. They just fired our VP of HR a few weeks ago and put the owners daughter as the Interm VP Of HR. Since then NO one goes to HR because they are fearful of their jobs. Im not sure what to do. It is very clear what is going on and when I said I will just resign from my position then if people are so fearful of me. They said no no that is not what we want you do a great job we just need you to sign this paper. I have been in HR before and understand when they are building a case. If this write up was because of something I actually did I would not be writing to you. However, the accusations are completely false and I did write that at the bottom of the write up.