NC for this but I've posted about my abusive exH several times.
After years of coercive control, verbal, psychological and emotional abusive via text, email, social services and the court system, I had no choice but to block him on everything and everything went via my solicitor. He doesn't have one which has never helped matters.
Last week he was threatening to take me back to court over a basic miscommunication of which I won't go into the details but I was not at fault (never am but that doesn't stop his court applications). I've been in that court 18 times with him in a handful of years and couldn't face it again so I decided to be brave and speak to him face to face at drop off to explain and talk about contact for next years holidays. He was annoyed the hadn't forwarded him the proposed dates and again threatened court. He likes court 
I explained the solicitor would be in touch and refused to get into it with him.
We agreed a few things and he managed to guilt me in front of the kids who'd wandered out into giving him extra contact this week. I had to agree or the kids would have been in tears and I needed to keep him on side to avoid court threats again.
Later we sorted a few adjustments via text which was all fine, no problems. But he's since asked for two extra days with the dc this week when it's my holiday with them and he's now pestering me about the solicitor and trying to get me to negotiate outside of that safety net. In less than 24 hours he's asked for 2 separate extra days and pushed me on the solicitor and dates for next year 6 times.
It's making me feel really anxious. I've got a constant sense of unease in my chest. I blocked him because of things like this and would do again except I am beyond anxious at the prospect of court again. He's been told by all involved such as the judge, cafcass, social services to stop doing this but still, every year, he takes me to court over contact and the court lets him do it as he throws in a malicious accusation of abuse each time. Contact runs smoothly except for occasional illness in which case alternative dates are offered. He's just using the system to continue his abuse of me. In our marriage he was sexually abusive and physically abusive in addition to all the psychological and emotional abuse. It took years to get divorced as he delayed it. He left for another woman so I don't understand his need to keep hurting me.
Anyway. How do I deal with this so as to protect myself from further issues with him? I have sent my solicitor screen shots of the conversation regarding changes to contact so he can't deny that. Should I just leave it with the solicitor now? Every time I get a text I get so anxious thinking what now? I want to block him but don't want to jeopardise what we've arranged so far and risk court because I'm "not cooperating."
Grey rock block doesn't help my anxiety as he just keeps texting the same things and pushing for an answer. I really can't deal with contact with him.
He's given us 6 years of hell and I wish he'd drop off the face of the earth but for the next few years I've got to have some contact due to the kids.