Google calendar synchronisation both sides miss

Hello.
Regarding this text on your web site :
“Synchronize all the reservation with your Google Calendar account also you can add new reservations from your Google Calendar into Salon Booking System plugin.”
I can expect that I can create a booking in the Goggle calendar, and this booking go in the Salon booking calendar in my web site.

Actually all is fine in my page with this (amazing) Salon plugin, the bookings go from the Salon system to the Google calendar. But if I make some booking in the Google calendar they don’t go in the Salon system.

I will appreciate an help. Thank you very much.

We plan to use the plugin in pro version (with app and payment) soon for our customers.

The page I need help with: [log in to see the link]