If a teacher does not provide a rubric for an important assignment, what should you do? The only right thing to do in this case is to ask for a rubric to be provided. You cannot play the guessing game, especially when it comes to a professor giving you an important assignment. They might have simply forgotten to give you more instructions.
Professors are also human and they, too, have a lot of work. Don't be afraid to come up to them and clarify any issue that is bothering you. Ask about their expectations from you, clarify the required format, necessary readings, and key points of research. If you think a professor is wrong or they are trying to fail you on purpose, you can try talking to a dean about it.
However, this is a serious accusation, so make sure you rule out all the other possibilities before accusing anyone of misconduct. Any such questions you can resolve with our college assignment help online service.