She sounds like she's testing boundaries the same as any kid in elementary or junior high school; each time she does something obnoxious and you appear to accept it, she escalates by a small amount and tries again.
Quick prediction: you have now told her, with legal authority behind your declaration, exactly what you will do if she continues to harass you, yes?
Even money says she will begin with very small incursions you can't legally stop (such as, for now, continuing to show up at your door to get the boys) but will be unable to stop there. Even money says she will escalate again until she's doing exactly what you warned her not to do, and when you take exactly the legal action you warned her you were going to take, what will be her response?
"I can't believe you're doing this! Why would you do this to me, when I tried to be so nice to you? Why are you always against me? I'm just shocked that you're so mean-spirited!" Etc. etc. etc. The general theme will be complete shock and disbelief that you did something so impossibly surprising and unpredictable as doing exactly what you said you would do.
I see this in the classroom every day. "I ain't fixing to do no [censored] work, so what the [censored] ever." "You can cuss at the Principal in his office if he'll let you, or you study quietly in here, but you can't cuss in this classroom. Which one do you want to do?" "Man, [censored] you, you think I'm scared of you? Ain't nobody scared of your old ass, mother******. Shut up talking to me!" "OK, go to the office." "WHAT? I was just playin'! How you gonna send me to the office just for playin'? What kind of racist mother****** are you anyway?" "I didn't know you were playing, and it doesn't matter. You know the rules, and I reminded you to to curse in class. I told you that if you cursed you had to leave. Then you cursed, so now you have to leave."
When someone is testing you, you can never give them enough warning, and you can never deal with them as if they were trying to get along with you.
