I hired a tree service to cut down a dead tree. They offered to do it for $1200. I signed a contract and paid a $400 dollar deposit by check before they started. They cut down about half the tree and asked for the rest of the money in cash with assurance that they would be back the next day. They came back the next day to clean up some dead branches. The rest of the tree is still standing. I have called repeatedly to get results. I finally left a message threatening legal action. What would that legal action entail and how do I go about it?