How to handle crazy ex 😩

My husbands ex is absolutely unbearable. They have 2 kids, which my husband has full custody of. We filed last year in April because the kids wanted to move in here, and she signed the papers without going to court. She’s constantly caused more problems since then, specifically keeps trying to say that we falsified the papers and that she only agreed to them living here for 1 year. That’s not what the modified divorce decree says lol. She has copies already. We even included in it that she doesn’t have to pay child support to help her out when he used to pay $800 monthly. This past week the kids got grounded, and she FLIPPED. No one told her they were grounded, she just assumed because she texted them and they didn’t respond. She went on and on saying my husband is the worst parent, the kids are scared of him, he needs to take classes on co parenting, that the “contract she signed is expired”. All bullshit. Even the kids said they’re scared of her they just don’t like getting in trouble, like any other kid. They’re 12 and 13 so they’re older and aware of things. We really try to never involve them when it comes to her, we just wanted to know if they were legit scared. We’ve never yelled but they do get grounded here when they disobey. Anyways, I’m just so beyond stressed. It’s almost harassment it feels like. She doesn’t stop accusing us of things that make no sense. And again SHE signed them over lol. She only has weekend visits. It makes me physically ill and have panic attacks when she does this. I’m 35 weeks pregnant and had constant BH while her and my husband spoke. He’s the most amazing father and it hurts me so bad. I wish she would literally just disappear.