Ex denying court mandated visitation?

hello, my step father had worked out child support(500 a month... on a 10,000 a year salary) but he delt with it and got his visitation for a weekend every other weekend(overnight) well she decided without telling the court she would move out of state(from south carolina to north carolina) without telling the court. he needs her current adress for paperwork, to serve her for denying visitation but he pays support through one county and it goes from that county to another to pay her. well the one that sends her, her checks, is not helping as they wont release her adress, how could we get it, and what charges/time would she be facing if we won. and who would get custody of his daughter?(she has full custody) would he need to do a custody hearing over that too, to get custody?