Technically, if the non-custodial parent has court ordered visitation, then the child and custodial parent have to comply with it. If they do not, then the custodial parent can be held in contempt of court.  As a practical matter, let's face it, you really can't force a 15 year-old to do anything.  You could go to court and try to get the visitation portion of the custody order modified but short of some sort of abusive or unsafe behavior on the non-custodial parent's part, you probably won't get anywhere.  Still, considering the "child" is over 12 the court may well give more consideration to their non-visitation request.  Just remember, the custodial parent cannot be found to have initiated or co-operated in any non-visitation incident.  Why not try to talk to the mother and see if you can reach some sort of mutual arrangement regarding visitation - possibly once a month.  Otherwise, you wil all need to take the time (and money if you have an attorney) to appear before a judge and possibly still not have things resolved they way in which your stepdaughter wants.