Students receive notifications after dropping course

[lrodriguez31]

I am a transfer counselor who is using Canvas as a continuous "course" that students can use as a transfer tool. Some of our students are on their way out and no longer need Canvas, so they dropped the course. However, they are still receiving our notifications. I reviewed the roster and the student has dropped the course and does not appear under People. How can students who drop our course stop receiving notification?x