Maybe the first thing they should have said to these people, was, I’ll see you in Court. And then do it. It may or may not make any difference, but it might put them through some changes.
It DOES make a difference. You would be surprised how fast attitudes are changed when they are physically served with a subpoena, especially during office hours. It can be a very inexpensive way to show you are serious and it is not a game. It is a very good ego shrinker and reminds people they are not immune from the consequences of their decisions.