Steph2, call around and find an attorney that will do a free phone consult. I did because I had a situation very similar to yours. My ex went for years being a back and forth parent. When DD was 12, she contacted him after 4 years of not seeing him or his family. She started going back to see him/them. It did not go well at all. She refused to go back. Ex told her she had to come or he would put me in jail. He told her that he would bring the law to "force" her to go. I kept telling him that he was welcome to exercise his visitation per our agreement, but I was not going to be the one to physically put my then 14 year old daughter into his car, he would have to do it. DD was scared to death that they would take me to jail and her to juvie or worse, send her to live with him. Finally, to calm her, I called a lawyer. I had to call quite a few of them because most don't do phone consultations. Well, suffice it to say that now DD goes to see Father and his family when she decided she wants to. According to the lawyer, she is old enough that a judge would listen to her about the things they did and said to her that made her not want to go.
In fact, she is going down to see his parents this coming weekend for the first time since Christmas.
If the kids want to see him, then by all means, work with him and them if he contact you. If they don't want to see him, I would not do a thing until and unless he contacts me, then I would go to a lawyer. Yes, you have a court order, one that HE has willingly violated for seven years! Make him enforce is through a judge AFTER you tell everyone that will listen that he walked off with no contact for those seven years. But, if he has gone this long, do you really think he will turn back up now?
-Life is too short for regrets.