Why won't they buy and use one of the commercial support forums, like
http://www.kayako.com/ , for example? It takes less than a day to set up such forum to send emails to appropriate people, and manage handling the tickets appropriately.
And then customers could make support tickets on the website, without the need to send emails, and in case the emailed answers don't get to them, they can periodically log in, check their tickets.
Email getting lost is nothing Bookeen couldn't improve on - if they wanted to.