The reason she gets angrier when ignored is that she needs you to fear her (her insecurities make a very needy ego). You are dealing with a very mean woman, but she is mean because she is like an injured animal (take the thorn out of it's paw,...easier said than done). She is the "MOTHER" and cannot let herself be seen as needy. It would almost be impossible for you to get through to her without violence, she will push you and your husband into violent confrontation with her (she is UNREASONABLE, she knows that she has to be in order to do what she is doing), but you might be able to get one of her friends to explain that you are not your mother's enemy. But don't say "please" (when you asked her not to threaten you, by acknowledging her threat as valid, you gave her "legitimate" ammunition and validated her "power"), "PLEASE" means she has got you on the run, you only encourage her when you do that. CALL HER BLUFF, but watch out, she will go behind your back and tell lies (in secret, that way they cannot be rebutted and you won't have a chance to defend yourself) in order to get you in trouble. She will talk to the counselor without your knowledge and ask the counselor to keep it quiet for some phony reason (whenever things are done in secret, it is so an evil scheme can be worked out). It would be much better for you to go to the police now and explain what your mother is like before your mother gets to them. If the police already know your side of the story, they will probably ignore her and then your mother will calm down because she lost the fight and cannot threaten you anymore. Maybe if you go with your husband and the literature that she marked up. It would look a lot worse if she got to the cops first. I could right a lot more about such a person, but I think you get the idea,...she is a MEAN person, she wants to see you squirm and she still won't be happy if you do that, she'll only want MORE. She will crush you if she feels like it IF you keep saying "PLEASE". She wants to be the cause of your sadness. There probably are times when she will be the cause of your happiness, control freaks do that in order to be known as the "Great Merciful One". First she will rag you (belittle you) out and crush you, then she will stop and let you cry in peace because she is "The Great Merciful One" fair and just (and in complete control of the situation with her mighty power).
Don't take her too seriously, say "All hail the great merciful one" when she threatens you. A little sarcastic mockery of "her mighty princess should calm her down (all appearances aside, she is sane and, deep down inside, knows better than to take herself seriously). A sense of humor fosters rationality, and she knows the only rational thing she deserves is sarcastic mockery.