My employer says things about me that are untrue behind my back?

I started a new job in July, having been with my previous employers for over 4 years with never a bad or derogatory word said about me from them. That being said, my new boss is constantly defaming my character when i'm not around. so far to date here some things that were done to me. About a month or so into the job (1) she went to the office biller and asked her why her phone bill was over $100 higher than other months. The biller went through it and highlighted all HER personal phone calls and promptly paid our employer, however according to the office biller, it was aimed more at me from what our boss said to her regarding phone calls. So, i promptly went through it and found one call for .15 to my home in August and never another call has been made since. (2) She accused me of changing a date on a "received" piece of mail which I did not do. This happened when i left for a few days for surgery i needed to have done. (3) Text messaging at work which i also don't do, but the other girl (the biller) does do it and she's african-american and has had 2 other lawsuits against former employers for race discrimination. Our boss has clearly seen and heard her phone go off repeatedly throughout the day, day in and day out on her desk but it always comes that I'm the one who is texting and I'm not. My phone is in my purse all day under my desk. Now I was out sick yesterday due to complications from my surgery and she said to the other girl (the biller) that she never heard of that happening to me. Also, the other girl (the biller) had texted me yesterday while i was recuperating at home in my bed and i texted her back and her phone was out and open on her desk and our boss saw that it was me texting her and said if i was ok to text i was ok to work. my surgery had nothing to do with my hands it was gynecological. I'm at my whits end. I can't take much more of this "witch" hunting on me that the other girl is doing it is ok for her to do it, to have her phone out and get text messages when i don't even do it!!! help me!!!!