Let me preface this with the statement that I recently earned my B.S. in narcissism (lol) through my divorce. Take what you want and ignore the rest, I don't usually give explicit advice. But every word and interaction with an N must be carefully measured.
The narcissist's game stinks and I'd rather not play. BUT, what I do in this case... is write the email I want to write, that I'd send to a rational adult who can look in the mirror and who could be held accountable to humanity. I vent, I rage, I plea.
I set it aside.
Then I write version 2...eliminating my emotion, because that's meaningless and only allows him to feel the control. As far as he's concerned, I don't HAVE any emotions...just like him. I cannot let him ever know what dents my shield. It's strictly business.
Then I write version 3, because I realize I still used too many words and secretly still tried to appeal to his lacking humanity. Less is more. I hate this part because I still want to say more and should be able to!!!
Version 1 is loooong. It's essential for my healing, and to learn how to reduce it to his world. Version 3 can't be more than a paragraph. Anything more than a paragraph is wasted, the courts tire of it, and he's not going to listen anyway. Can't include any emotional words whatsoever (they don't even really understand those).
So...if you must send something... just bluntly state his failure (which will incite rage, most likely, because it's FAILURE).
And never let the anger through. You'll end up upset that you let him see that. I also gave up any use of "hi", "thank you", etc., because I'm not going to thank you for being a minimalist human being. These aren't thank-able events.
Here's a good one for documentation that I'd use here. Remember-- the REAL stuff- when he listed the rental, etc.-- those are documentable outside of this email. You can pull those if needed in court so you don't need them written here. (That's hard for me, I keep hitting myself over the head with this, because things like this are so ridiculous I want to scream them and show him I KNOW he's doing them... but that's for a different satisfaction than winning on my kids' behalf. So I stifle it. You WILL get your validation, but not yet.) It's a long, stupid chess game.
Here goes:
Update
Our children need basic living supplies. Just like last (week/month), they still need x (shoes, clothes). You've sent nothing. Their needs have not changed.
That's the whole email. Seriously.
For tracks, this is clearly letting him know there are needs so he can't claim ignorance. Not asking him what he'll do, because he's not going to do anything anyway and you don't need to tell him what to do. A responsible adult KNOWS what to do and will do it. An a$$ won't.
He will likely send you a verbose email back full of vague untruths that you feel the need to defend on paper. Think carefully about that too. In many case you don't want to respond. (And you'll be pretty darn angry, but that's okay. He's crazy. It's not you.)
PM me if you want to talk. I've been playing this game for 18 months. And I'm gearing up for yet another war...