Don't worry, we'll sort it out together. Contact us and tell us which class it was, and we'll remove the missed check-in (and any fee) for you. Please note that we can't keep doing this retroactively indefinitely.
So make sure you check in yourself from now on when you're there; the sports location can't do this for you. Turn on the reminder (push notifications) in the app to get an automatic prompt to check in, so you won't forget again.