Did construction for/with my landlord over the course of 11 mo. he has not paid me in full, and says he won't, what are my options, have issued 4 inv.

I was assisting in readying a 16 Appt. complex to sell and it is now on the market. We had a verbal agreement, and I have much printed and hand written correspondence and documentation. We worked together often, saw each other most everyday. I have testimony from many of the tenants as to work performed, however they would rather not get involved. As he is planning to sell and I want to put a mechanics lien on the property. Did many managerial tasks as well have worked up until just before Christmas, 2018. I have issued statements left messages and visited , bu t he won't respond!