my home is listed for sale. A unlicensed contractor stopped working for me by mutual agreement on October 26 2018.The cost construction est.at $90,000. On October 2 2019 he e-mails a bill for $ 17,327.22 for remediation that he never did- no dates provided.I requested dates the work was done.He does not answer my question. If i refuse to pay him, can he put a lien on my property?