Syncing calendars

I have a problem with double bookings. I have set up booking.com to synch with my calendar for my website's direct booking.

I have set up my calendar in a way that when booking.com imports my calendar I log the timestamp somewhere. from looking at the timestamps for today, booking.com last imported my calendar this morning at 07h02 (5 hours ago).

This frequency creates fertile ground for double bookings, which booking.com does not take responsibility for.


Does anyone know how often booking.com imports external calendars? 5+ hours is just too long.