Trying to find out if unlicensed window installers demanding final payment prior to completion and final inspection have lien rights. Company A are unlicensed installers that we paid 50% upon order of windows. Total price includes old window removal and installation of new windows with balance due upon completion of installation. Foolishly we paid the 50% without getting a partial release of lien. Company B is the Certified Building Contractor on the master permit. Company B also provides the insurance. We have had no contact with Company B. Company A just served the NTO on 1/25/20. 12/5/19 was the first day Company A came on premise to start work. Is this a valid NTO?