My husband and I worked on a remodel of a bathroom for several days. Now, they don''t want to pay us. What can I do?

My husband is a contractor craftsman. We worked on a remodel of a bathroom for several days, and heard nothing but praise for the beautiful work. We were about 80% complete and now the homeowners don¿¿¿t want to pay us. In fact, they have informed us that we own them for unprofessional work and material used. We left off the site because of the woman''s behavior; when my husband was removing his tools, she was telling him if he didn''t stop, she would call the police. Is this a breach of good faith? I would like to take the two of them to small claims court, but I don''t know what to call this. I have a feeling that they did this to the person before us. They were unable to get the person to return after a year. With the state of the economy, this is a red flag to me.