You can delete the class if you have imported it by mistake or no longer need it.
To delete the class, you first need to archive it. You can do this by going to the class page and clicking on three dots on the panel, and in the pop-up list, choose "Archive the class":
Then, in the "My Classes" section, you will see the "Archived classes" subsection. Choose the one you want to delete and click the following button:
After deleting a class, students will still have access to it and the activities that have been assigned.