Legal Question in Family Law in Massachusetts

File a complaint contempt with the court and seek an order instructing her to allow you visitation

If there's already a filing in court that grants you visitation time, you would file a complaint for contempt. If there's no prior filing, you would have to file a complaint for custody, support, and visitation (if you're not married), along with a motion for temporary orders.

File contempt action against her if there is custody and visitation Order. Otherwise, if there is no custody and visitation Order and if you were not married to the mother and you have not formally established paternity of the children, then you must first file for establishment of paternity and once that is resolved, you would then file Complaint for Support, Custody and Visitation.