Deleting appointments in A+ back-end does not delete gCal entry.

Hi!

My clients will use my site to book photoshoots. The plugin works fine and they can book via the front-end of my wordpress site without logging in.
My gCal is synced with A+ and all bookings are placed immediately in my gCal.

I will not touch the gCal, using only A+ back-end to edit or delete appointments.
The problem is; When I delete an appointment in the A+ back-end it is not removed from my gCal.

Do you have any suggestion on how to fix this?

Thanks in advance.