Got told by my boss that I created a hostile work environment?

I was sent to the accoutning office today by my manager Dedra Giles exclaiming that I had caused a hostile work environment for her and her management team because I had written a letter to the company stating how they had been treating me. In purposely giving me low scores and and pointing and talking negatively about me to coworkers and now she is saying that i make her feel like she cant even come around me. She said everything I had written to the company was a lie and that they werent going to do anything about it! Also I found out today that she has been telling coworkers that I have been leaving the restroom messy all the time! I really feel like I am being victimized in this situation and I need to know what it is that I have to do in order to make this stop!?!