Guests using Insta Book that have not completed verifications causing my calendar to be blocked.

[Gerry-And-Rashid0]

Yep....even though you say 'only verified guest' AirBnB takes that to read as guests who have started to go through the verification process. And, in the meantime, as you have discovered they have blocked space in your diary.

It's shocking behaviour as you would have said no to that guest and asked them to come back when verification was complete.

[Mike77]

Turn off instant booking.  Maybe that will open up your calendar?

Mike