I'm not really to sure how you got your grade if it was already out and you have received an F already but if not then it is still a course to fight for. I had a course which I really thought, with me computing my grades that I already have failed that is still until I took our final departmental examination and I turned out one of the top student for the course in the whole uni. So I believe until the grades are turned in, you can still fight for it.