@leofromparaguay Bah...sounds awful. Here's what I'd do if I were you:
1) Write an email and spell out some ground rules. Your ground rules should be things you'd like to see changed to treat you more respectfully. No name calling, no fights in front of the kids, no yelling, etc... You'll know what things make you feel uncomfortable. Have consequences to your ground rules. Things like "I'll terminate our meeting if I'm treated disrespectfully." Be prepared to follow through. It will take a couple of tries for her to get the message.
2) Start getting the kids report cards directly from the school. Now the schools put those online for parents to look at. That will be one less meeting you need to have
3) Stop having meetings in person and/or at your residence. Try and take it to writing or over the phone. People problem solve better in writing.
4) Start documenting. Write these incidents down with dates. Try and keep your descriptions neutral in your journal. Adopt a "just the facts" approach and leave your emotions out of it.
I've written a couple of different responses on here from the non custodial parent's point of view when dealing with a high conflict or personality disordered Ex. Check those out so I don't repeat that information here.
My experience with alienation issues is that it has to be to the extent that your child no longer wants to see you. At least that is what our attorney told us in our state. Check with an attorney in your state to find out what level of alienation is required to motivate the courts to act. Custody modification is extremely difficult to pursue. You could be looking at a very expensive legal battle. We were told we could be looking at around $40,000. One of our daughters is over the age of 12 and can now legally be heard by the judge. She repeatedly expresses a desire to come live with us. Even with that change in circumstance we were told to be prepared for an uphill battle. The court does not like to uproot children from the parent who has been taking care of them. The court does not like to split siblings up.
Go check out "TheProperPerson" on YouTube. He is a father who won his custody modification in Utah. He did it for the most part without using an attorney. He started with supervised visits and over a period of years progressed to sole custody where mom lost her parental rights due to all the shenanigans she pulled. According to him mom spent around $100,000 on her attorney fees. High conflict cases are expensive and they are a gamble. You don't necessarily know how the judge will perceive you vs. her. Courts in my state make you go through mediation first.
Good luck and all the best!