School districts

My husband was deported to Mexico about 3 yrs ago. I live in a border town and frequently go into Mexico and visit. i recently was stopped by the school district and was told my children are not allowed to go to Mexico as long as they are in the school district. The school district has advised that if they are caught again crossing the international bridge, the school district is going to withdraw them. They are american citizens and I do pay my taxes.I feel my rights have been violated and need some help. Can anyone help?