Regardless of the user-base, there will always be a small segment which accounts for the majority of your business's support costs ( filtering / banning / rate-

Regardless of the user-base, there will always be a small segment which accounts for the majority of your business's support costs ( filtering / banning / rate-limiting / etc ). The best advice I can give you is that you have to treat every user as a good customer until proven otherwise. The last thing you want is false negatives affecting your revenue stream and alienating potential customers. It's unfortunate you are experiencing issues. Do your best to keep internal metadata on every user you interact with. Document and tag all related support communications. Get a good CRM. Once you've collected a bit of data, look for common signs of a troubled user and see if you can make any changes to policy or software to prevent future issues.