If you have the free version. If you changed the admin email of the blog and the reservations are still going to the old email address. You need to try deactivate and the activate plugin. If this will not help so then You need go to the Settings page of Booking Calendar, check checkbo Delete Booking Data ( This operation will DELTE ALL SAVED BOOKINGS durng deactivation !!!) and then try to deactivate and activate plugin?after this you will have New emeil admin adress is set for the bookings.