Appointment + problem

We have been using appointment + for some time now and it has worked well. Suddenly today there are dates on our calendar showing as available when they are not. And even when I add these days as an exceptional holiday, they are still showing as available. This is a disaster for us! Please get back in touch asap to tell me how to reset this. You can see what is happening on our webpage There should only be Mondays showing for Woolwich and Tuesdays only for Catford.
Thank you, Joe