The contractor did a very unsatisfactory job. As consumers, we had to hire somone else to finish and correct the work. We paid the contractor $3,600 on a $4,181 contract value (with a serious defect in the definition of the work to be done) He says it is something, but we say it is what we asked upon initial discussion with photos of the results wanted. We paid him about 85% of the sum ($3,600 for 6 hours work) asking him to come back and remediate the situation. Also telling him that he would get the balance upon finishing the work. He is laughing at us and is now threatening us with a mechanic's lien. What should we do. He did not complete the work but he says he did.