These flags are probably temporary (I've been told that my account is flagged and I got credits a few months later). I think it's just a note on your account, flood 'em with tech support, billing and customer service inquiries and the "flag" with get lost in all those notes.
They had (and I think they still have) a rating system where they rate how profitable a customer you are, and the higher the rating the easier it is to get credits.