Hi there, @AlessandraCarri ...
You've posted your question in the global Canvas Community website. This is different than contacting the Canvas Support team that works at Instructure (the company that makes Canvas). We here in the Community website are fellow users like yourself (instructors, Canvas admins, Instructional Designers, developers, students, etc.) that all use Canvas. Unfortunately, we do not have access to your school's Canvas environment or any of your courses. So, we cannot help you open a quiz that has been closed. I'd recommend reaching out to folks at LACCD who are in the Online Learning / eLearning / Distance Education department there to get further assistance. Hopefully, someone can work with you to investigate this. Ultimately, they may have to contact your instructor again to provide some "how to" instructions. There may be a setting that your instructor needs to change, for example.
Good luck to you!
