I hired a contractor to repair my retaining wall. He made it too short and not nice. He said he had finished the job as far as he concerned and I need to pay him the remaining balance immediately, otherwise, he will tear down the wall. I called the police to prevent him to enter my property. The police told me that yes he could tear down my retaining wall without my permission if I did not pay him immediately. Is this right? I can not prevent someone to enter my property after he performed some work.