Ex-husband wants terms of 13B modified

I got divorced through mutual consent.The custody of my child remains with me. However, I have agreed that my ex-husband can visit the child on a weekends. Now, my ex-husband is remarried and lives in US. He tried calling me and wanted to talk to my child, which i did not allow (As i have not agreed ). So he filed a case in family court for allowing him to call the child and make the child visit him in US. As the judge told him that the terms cannot be changed, he withdrew the case, Now,i have few questions regarding this situation. 1. Can he go to higher court with the same appeal and can the higher court change the terms of agreement in 13B. 2. I have remarried too and my husband lives in another country. For my child to get a residence visa in that country, an NOC has to be given by the child's biological father. But my ex-husband is not giving us NOC and making me undergo a lot of stress by filing cases. He has no love whatsoever for the child, by doing all this to trouble me. I am unable to live peacefully with my husband because of him. What can be done now? Please suggest