Courts really favor joint custody as they believe that it is in the best interests of the child to have a relationship with both parents.  I think what you really want is to be the custodial parent, meaning that your son would live with you most of the time and your ex would have visitation, much like you have now,  More information is needed to determine that issue but what you do have is a date with a Judge on a motion for contempt and interference with your parental rights.  Get help.  Good luck.