Hi Rubin, I had this from my ex years ago too. Sadly I don't think there's a law that's going to work on your side, except if it got to court they may put it in the order if you insist, you still can't make him take them though.
He sounds as though he's getting a lot of pleasure in controlling you still, and whilst you give him the reactions he wants, the games won't stop. My advice (which took me years to actually be able to do) ignore his texts or just reply 'ok'
Don't be drawn into these petty arguments
My ex complained about phone calls too, he'd call twice a day. Dc had nothing to say to him. He brought it up in court and their attitude was that the dc are small, don't like the phone much, you can't force them to talk.
Let them answer the phone, don't get involved, they'll leave the phone on the floor or show him things etc. you'll then be criticised for not managing them etc.
You won't ever win against this type of fuckwit. So stop trying.