... tell me to “stop running to the cms”
Intensely irritating, & my gut reaction would have been to immediately "disobey" his order! - can see how frustrating & enraging he is from that comment alone.
now has disappeared again! It’s been 2 months now. That’s the last time he messes with their heads.
Bloody good for you. Just having that sense of resolution is so freeing.
... has told me he will never ever step up, I have it down in black and white, he said he will never be a dad.
Beyond the hurt & sorrow of that ... brilliant. You have it in writing. You can now choose what to do with it.
One choice would be to ask him to agree (sign to) never darkening your or kids' door again - on condition of which, you agree to not go "running to the CMS" (gggrrr) or expecting a single penny from him for his children.
There's a downside to that though, because it looks like he's the type to immediately pounce on the fact that as you want no contact from him, he can continue to mind-fuck you by refusing to comply. Would he be that type? - would he then make it his life's mission to turn up randomly, raising & crashing the kids' hopes time & time again?
If you think that's a risk, another option could be just one 'final' text from you, saying something like - ok, you win - I'll tell the CMS to stop chasing you (ha! he needn't know your difficulties with them) - but only so long as the kids & I never have to see you again. I know that not ever paying for your kids is more important for you than seeing them, so that's the deal. Take it or leave it - but be warned - if the kids or I see a hair of your head, I'm straight back to my CMS documents so they will come after you for what you owe.
Let him think he's "won".
Then block him on all phones & media.
So much easier for you & your kids, it must be heartbreaking to see them let down & messed about.
Stay strong, you're already way wiser & tougher than a twat who uses his MH issues to manipulate you with & treats his childen so badly.