What to do here


Both of my children are failing school for the second year in a row. my ex doesnt seem to care either. In fact both boys were held back a grade last year due to failing performance in school. She has what in our divorce papers is called residential custody. I have liberal visitation and in fact it has really been less than liberal. I went almost 6 years without even the smallest contact with them. then last year I finally started being able to see them, and in fact got them for most of the summer and Christmas break. My ex has since remarried and now has 6 children to care for including 1 born out of wedlock (the father isnt around) 3 of the new spouses kids and my 2. During Christmas break she was suposed to be moving to Texas(new hubby is in the Army) from SC. I picked them up on Dec 18th from charleston SC and was suposed to return them on dec 29th. She was suposed to meet me half way while on her way out to texas. The date came and went no contact from her. Finally around the 3rd she calls and is like we havent moved yet and could I put them on a plane to Texas so they could stay with her sister till she got out there. (my children had never met her but have had phone and I guess IM conversations with her ) I was like I guess so but arent they supposed to be back in school soon. She was like my sister is enrolling them in school there. I have already sent their school records to her. I figgured I should at least talk with the aunt and make sure every thing is on the up and up. Instead of a conversation directly with the aunt I ended up on confrence call with my ex basically dominating the conversation. The aunt did seem genuinely concerned over their schooling, and kinda against my better judgement I said yes. (Im finally getting contact with my boys but have to play by my ex’s rules diddnt want the contact to stop after the return) The next contact we had was on jan 5th I asked if it wouldnt be better if the boys stayed with me and finished the school year here. After all they were struggling in school, and we had already returned to school here. She was like “it aint happening the boys are failing because they want to come live with you thats what they want and Im not going to let it happen your not stealing my kids from me”. I conceeded didnt want this to escalate here. The next day I get a call can you have the boys at Charlotte airport at 6am tomorrow? Against my better judgement I agreed (I live in Hendersonville). I get the boys to the airport to put them on the plane.Every thing is in order which I had prayed that it wouldnt be. I know from experiance only a parent or legal guardian can enroll a child in school here in NC and not really sure how it was pulled off out in texas, but they are back in school. They are doing better the aunt seems to really care about their progress. I find out my ex has finally made it to texas as of tuesday the 24th of jan. She isnt even living in the same town as my kids, and in fact is living about 3 hours away. The kids are scared she might come and take them from the aunt and they will be failing again. Im almost positive of that after all 2 kids are a challenge but 6 has got to be even worse. I guess all this is leading up to the question of is there anything I can do to get my kids back and have them live with me and my new wife? and what court would I go through? We were divorced in florida she has since lived in Florida, Oklahoma, Texas, South Carolina and now Texas again all the while I have been living in North Carolina.