Twilight Zone Nightmare

I have been working in the same office for about 10 years. A few years ago a new worker transferred to the office. She was assigned a simple task picking up the mail. Most days she would "forget" to do this task. Supervisor said nothing.

Few years later, she's molded the office to her control. Spends hours each day on personal calls. Some lasting 20 minutes to an hour. Surfs the net, long lunches, socializing with her friends instead of working,wanders in and out all day. But that's not enough. Now she's spreading lies about me and threatening me openly. Supervisor looks the other way to all of the above. Have no proof of threats.

Now I am being mobbed by her friends. No one to support me.