University will not let me use scholarship?

I graduated a few years ago with a BA in Economics. After much soul searching, I discovered that I chose the wrong major. I want to go back to the same university and do everything over again with a new major. I had received a full scholarship because I was at the top of my high school class, but the university will not let me use the scholarship for a second degree. I do not have the original scholarship documents anymore, but I don't remember any requirement about only pursuing 1 bachelors degree. I have spoken with everyone in the university, but they will not budge. I am considering legal action against the university and I was looking for advice. It is not fair for them to not allow me to use a scholarship that I earned through hard work.