At some point I wouldn't do their work anymore.

It is not our job to educate our clients, at least that is my viewpoint on the subject.

I had a client once where the  examiner in the company was nasty, and I mean nasty, she would call me daily and expect me to work out the current legal on the property DESPITE the fact that she was sent all the deeds so she could work it out herself, that was the job she was being paid to do at the company.

After a month of this I called my contact at this company who was actually very nice and told her I could no longer do their work and she ask me why, I told her and she actually agreed with me.

Then  the nasty one called me when she heard about this and was screaming at me on the phone, and after about 30 seconds I said I am hanging up the phone now and I did hang up on her.

She then called me back and I did not pick up the phone and deleted her message.

You must have the patience of God because I would and could not put up with that kind of stupidity!!!!!!

Sounds like these people you are having to deal with