Denying Visitation
Parents should not be overly concerned about adhering to the schedule in a strict fashion, because they are typically designed for some flexibility. The courts hope that the visitation schedule is one that will influence a well working relationship between the two parents, which the children will ultimately benefit from.
If you or the other parent has decided to deny visitation, hence stripping the rights of a parent, the court will not be very happy and legal action should be taken at the earliest possible moment. There are very few reasons that a parent should deny visitation and if so it should be done properly through the court system with an official modification to the existing custody and visitation order.
If you are worried about the well-being of your children, do what is right and contact a lawyer in your area to pursue your situation properly through the courts.
Also, denying visitation due to delinquent child support is not permitted. A custody order and a support order are treated separately by the courts.

