There could be other reasons for the motion to modify than those related to your income and what you've been paying. For example, child expenses could have increased or her income might have gone down. As you know North Carolina uses child support guidelines. Under certain circumstances the court can vary from application of those guideliens.
I suggest you consult with a local attorney to see what your options are and risks are then make a decision about whether to go into court alone or with an attorney.
LEGAL DISCLAIMER: SCOTT ALLEN IS LICENSED ONLY IN THE STATE OF NORTH CAROLINA. THIS RESPONSE DOES NOT CONSTITUTE LEGAL ADVICE AND DOES NOT CREATE AN ATTORNEY/ CLIENT RELATIONSHIP. RATHER, THE RESPONSE IS IN THE FORM OF LEGAL EDUCATION AND IS INTENDED TO PROVIDE GENERAL INFORMATION ABOUT THE MATTER IN QUESTION. ALTHOUGH A RESPONSE IS PROVIDED TO THE SPECIFIC QUESTION, THERE MAY BE OTHER FACTS AND LAW RELEVANT TO THE ISSUE THAT THE QUESTIONER HAS LEFT OUT AND WHICH WOULD MAKE THE REPLY UNSUITABLE. THEREFORE, THE QUESTIONER SHOULD NOT BASE ANY DECISION ON THE ANSWER, BUT SHOULD CONFER WITH AN ATTORNEY IN PERSON ABOUT THE SPECIFICS OF HIS OR HER CASE
As a general matter one does not need an attorney for child support matters. The question I have is whether your child's mother is represented by an attorney. In these situations I'm reminded of Friedrich Nietzsche's famous quote "is it better to out monster the monster, or be devoured by it." The "monster" I'm referring to of course is not the opposing attorney. Rather, it can be a monstrous ordeal to navigate family court, especially as it relates to child support against someone who presumably understands and practices in family court for a living.