Appointments+ is not sending me confirmation emails.

I just lost 2 bookings because the plugin is not sending me notifications half the time.

They were going to my spam folder originally, and I created a filter to prevent them from going to spam, but now I'm not getting them at all. I just had someone test to see, and I got a confirmation email the first time, and the 2nd time I got nothing. The appointment is there in appointments but I can't check that every 5 minutes to see if we have a booking. I need to get these notifications. I am about to get slammed with bookings, and this needs to work.

Any help is greatly appreciated.