N.C. Gen. Stat. § 44A-24.10: Lien extinguished for lien claimant failing to file suit or answer in pending suit within 30 days after service on owner.

If a lien claimant fails to file a suit to enforce the lien or fails to file an answer in a pending suit to enforce a lien within 30 days after a properly served written demand of the owner, lienee, or other authorized agent, the lien shall be extinguished. Service of the demand shall be by certified mail, return receipt requested, or by personal service. The claimant shall file proof of properly served written demand with the clerk of the superior court. The provisions of this section shall not extend to any other deadline provided by law for the filing of any pleadings or for the foreclosure of any lien governed by this Part. (2011-165, s. 1; 2012-175, s. 12(b).)