Once your XML connection is enabled Booking.com is not sending any more email confirmations about new or modified bookings.
That is why, we developed our own notification system, which works ONLY for Booking.com emails.
In order to receive notifications about new or modified bookings from Booking.com, please make sure that you entered your email address into ADMIN / HOSTEL DETAILS.
If you email address is not entered, the email notifications will not be delivered.
If you don't know where to find this setting, please have a look here: http://screencast.com/t/7JxedAQA