I'm sorry no one answered your question. I know that there are talented attorneys from your state who answer questions on this forum. Perhaps reask your question and someone will be of assistance. Lots of luck to you.
Mr. Reimer is licensed to practice law in NJ and NY. His response here is not legal advice and does not create an attorney/ client relationship. The response is in the form of legal education and is intended to provide general information about the matter in question. Many times the questioner may leave out details which would make the reply unsuitable. Mr. Reimer strongly advises the questioner to confer with an attorney in their own state to acquire more information about this issue.
Your ex-husband does not have the right to go to school and take the children if it is during the time they are supposed to be with you. He can pick them up if it is during his time for contact pursuant to the divorce order. Can he withhold them from you when there is a court order stating they are to be with you? I think that is a no-brainer. Of course not. He cannot pick them up without your permission either. Practically speaking though what can you do about it? The police generally won’t get involved in trying to assert rights in a divorce order. Give the school a copy of the order and make it clear to the school he is not to pick up the children except during the time contemplated in the order. If he is withholding the children, my suggestion is either file for contempt (but that will take several weeks to get heard) or file a motion to modify and a TRO at the same time. A TRO is an action for injunctive relief. It is a mechanism for the court to order your ex desist in his actions and can be enforced by law enforcement. You can only file a TRO when there is a complaint of motion pending already in the case (that is why you have file a motion to modify at the same time. To prevail in a TRO is difficult. To file a TRO, you most likely need an attorney. It is far too complicated to go into in this forum.