My ex pays CS to his state, then his state pays my state, then my state pays me. As complicated as that sounds, it's much easier than dealing with his crazymaking and excuses. He was late once, and his state sent him a nastygram and that was the end of it. If I had been dealing with him personally it would have been a whole different story, I'm sure.
I agree with keeping things according to the court order. It might be different if you were both reasonable people working together toward the best possible outcome for your children, but this really does seem to be all about him jerking you around trying to feel like he has control.