What are my options a father with 50/50 custody when the ex refuses to give our child to me on my time

It is difficult to assess from the limited facts provided.   In order to change 50/50 custody, the court only needs to find that the 50/50 custody is not working.  If your ex is being an obstacle and the court agrees with you then they may hold her contempt.  You may want to try counseling with your child to help repair your relationship.