Hello @Allen312 ...
Are you sure that you are in the correct course when you want to de-cross-list? You need to be logged in to the course where you had cross-listed all courses. For example, if you had courses A, B, and C ... and you wanted them to all be cross-listed together so that all enrollments were contained in course A (you would no longer see enrollments in courses B and C). If you wanted to de-cross-list those courses, you would need to log in to course A, go to your "Settings" page, then go to the "Sections" tab. Next, click on the section name you want to de-cross-list (for example, course B or course C), and then you should see a de-cross-list button...as described here:
Hopefully this will be of some help to you. Sing out if you have questions...thanks much!