N.C. Gen. Stat. § 44A-24.11

If a claim for a lien has been filed pursuant to the provisions of this Part with the clerk of superior court and the claim has been paid in full, or if the lien claimant fails to institute a suit to enforce the lien within the time as provided by law, the lien claimant shall acknowledge satisfaction or release of the lien in writing upon written demand of the owner promptly, and in no event more than 30 days after the demand.