What are my rights regarding the re-use of a paper in college that I previously handed in for another class?

Question Details:

My university uses a website to check for plagarism on papers/essays. Upon reusing a paper I'd already written, my professor informed me my paper was red flagged by the system and he could not give me a grade for the work. The paper came back has having been previously used by myself. In no policy or rule is this referenced to or stated as being a violation. Can I actually be penalized for a rule that doesn't exist? If this situation was anywhere in the school's academic integrity policy or rulebook I would be out of luck but it is not. The rulebook reads "the use of another's work without credit".

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