Fraud Record, for Blesta would be amazing in my opinion, it checks a database for unwanted customers, it's a bit like a neighbourhood watch team, but for webhosting.
Any fraud gets submitted to the database, and you can check to ensure you don't get the same unwanted customers.
Stop Fraud Clients, Report Abusive Customers. Combine your efforts to fight misbehaving clients.
I used to use it on the last billing system I used and it helped much better than Maxmind, because bad clients are bad clients.
http://www.fraudrecord.com/
API: http://www.fraudrecord.com/developers.php