More information is required to answer this question. Where were you and he living at the time of the entry of the original order? Was the Order entered by a general Court or was it a child custody specific court, such as a "IV-D" court? Since you've lived in NC, how have the payments been made/collected?
My advice, which should be narrowly construed based upon the above questions, is that you should go to your county Department of Social Services and see if they are willing to intervene and take actions for you to modify the support Order. If they are able to do so, you will not hire a private attorney, but the attorney that represents the DSS will present your case to the Court.
Most states have adopted uniform laws regarding child support enforcement. Even if your case was originally in another State, it is likely that you can hire a North Carolina attorney to register an out of state order and then move the Court to modify and enforce that Order.
Go to DSS first and make an inquiry. If they can't help you, go see a lawyer in your area who handles child support cases. Good luck.
The information provided in this answer is for informational purposes only. This poster does not intend to form an attorney-client relationship with the author of this question. more specific questions should be posed to an attorney local to the area where the question originated and who has an attorney-client relationship with the author of the question.