It may be that you have more than one client associated with a particular email or phone number. To find out if this is the case, go to the clients page and search for the email or phone number that received the notification. If you see more than one client show up, this is likely the cause. If you're having trouble finding out who made the booking, e.g. staff or client, mail us on firstname.lastname@example.org and we'll help you get to the bottom of this.