We wanted to move back to pakistan but my ex made a big fuss even though he has not seen the kids for 3 years and the judge in the case said he was to have no contact what can I do if I go and not *** back can they do anything?

I'm confused, the judge ordered no contact yet refused to allow you to move? That doesn't make sense.

If the children are American citizens then you will need both parents agreement to leave the country. So get an attorney and go back to court.