Demand a lawsuit. He then has a few months to get his act together or waive the lien. Don't pretend like this lien doesn't exist -- he has two years to sue you and many contractors do wait until the last minute.
If he brings suit, do a combined 615/619 motion and attach the signed lien waiver, as well as indicate there was no written contract. Seek costs for this frivolous lien. I assume it is in Chancery? I have worked on these cases before and some judges are more eager to dismiss/award costs than others.
Retain a good mechanic's lien attorney.
This answer is intended as informational only, and does not constitute legal advice or form an attorney-client relationship between us.
Additional information is required to give you the best advice that you seek. For example, was the lien you received was from the contractor who you received the final lien waiver from or a subcontractor? You may very well have a defense to the lien, but it does depend upon facts and details that aren't provided. You would do well to speak with an attorney regarding your situation.
If the lien was maliciously recorded, clouding title to your real estate, that would be sufficient to support a claim for slander of title. Sit down with an attorney and all relevant documents to discuss. Good luck.
Robert T. Kuehl
Kuehl Law, P.C.