What to do about an incorrect final grade that was given to me?

<p>I finished a class a cleared an A(92 percent) but the teacher gave me a B. I have all documents and proof showing that I got an A but she made up some bogus excuse when I emailed her that she decided to grade everyone different because one of her tests had a bonus question. I have no idea where to go from here. Anyone have this problem and know what I can do?</p>