Hi @MarioMata ,
In addition to the information provided to you by @DrTerriC and @dbrace , I just wanted to provide some additional information. As mentioned, you should be able to unpublish your course as long as there are no graded student submissions. Even if your course does have submissions, if there aren't any graded ones, then you can still unpublish your course.
However, do note that if you are using a paid canvas account for your school, your school's canvas admin has the ability to prevent teachers from unpublishing their courses after they publish it. If that is the case, please reach out to your school's canvas admin for assistance in unpublishing your course.
Hope this helps!
Noah