Reoccuring meeting - Invitation cancellation

Hi there, I had a reoccurring meeting which I have cancelled, however, my client says that it's still in their diary.

This is creating confusion and I'd like to insure it's deleted for all parties. The reoccurring meeting has been cancelled now for over two weeks so I can't access its settings to see what's going on. How can I ensure that it gets deleted from everyone's personal calendars?

Thanks, Gabriella