Claim of Lien was timely filed and notice sent certifed mail to owners address shown in the tax records, sender received a signed return receipt, the defendant owners raised the issue in their original answer; but dropped the lack of service claim in their amended answers. On Plaintiff's Motion for Summary Judgment the Defendants argued they never received the Claim of Lien. Am I correct that the owners are barred from raising this argument since it was not in their amended answers / responsive pleadings.