problem's with ex

I am fed up with my ex threatening me. What should I do??? I have always done everything he has asked for my kids sake but now he is belittling me to them and me. I recently moved to an area that is aprox. 40 miles from his door step to mine but that put the kids out of their current school district. I live in GA. I am commuting the kids to their schools rather than moving them mid stream. I would love to keep them in their district but the school system does not make exceptions so for now I have not advised the school of our move. Ever since our move my ex complains about the distance and says that he will not make the drive. He is constantly asking that I meet him rather than him picking them up and delivery them at home. the last time I agreed to do that on a pick up come Delivery time he would not bring them any further than where I met him on Friday. My ex told our 11 yr daughter that he could not pick her up from the house until 6:30 rather than 6:00 as the papers state. When I agree to wait but ask that he be there no later then he suddenly cannot make that time either. He said to her well I will just see you in 2 weeks. I had plans that night anyway so I could not spare alot of wait around time. I waited anyway to see if he would arrive and still 1 hour later he did not. Our oldest daughter 14 was at a game and was to be picked up later but since my ex made the statement to my youngest I went on and picked her up as well. He got furious because she was at her school and he planned on running over to pick her and leaving the other at my home over weekend. Needless at 12:00 (midnight) an officer calls saying to me that he is filing a contempt on me and that I will be arrested for denieng the father his visitation. YIKES! Now, my ex, has threatening me with this and telling my kids if I am arrested then they can live with him and he is looking out for them . He is also telling them that he is going to tell the school that they are out of district and then the girls will have to relocate to where we live. I am trying so hard to to keep theie welfare at hand but I hate this threat. He is waving over them as a tool to force me to do as he wants. I am not sure what to do. If I move the kids from school now how will that look on me? I know it will upset them because of their ages and friends and it so important to them to stay. How do I stop this constant ya-ya with their dad? Also, the officer told me that he has the right to pick them up anytime thereafter 6 on Friday. Why is it my papers do not say that if it is true? How do I know ?????