. Capcha does not recognise correct answers. I have tried dozens of times to post suggestions and reviews but have succeeded only once.
I checked that, for me all work good, Can you send admin and ftp access to yours site and we will check where error, Yours account details please send with help ordasoft contact form
2. On the one occasion that I succeeded in posting a suggestion I received no email notification
For take email notification for suggestion in Book Library - you need set settings for email notification in BookLibrary settings.
Also you need configure mail setting in Joomla Global setting and check send mail in joomla articles first.
Also it strikes me that we need to be able to moderate reviews.
You may configure send review notification also