Joe Went to Sam the Barber for a Haircut

Joe went to Sam the barber for a haircut. When Sam finished, Joe looked in the mirror and was shocked at what a terrible haircut he had received. He refused to pay and got up to leave. Sam refused to let him go and insisted that Joe stay while he phoned the police. Joe did so. When the police arrived and Sam explained the situation to them, they told him that they wouldn't arrest Joe, and Sam would have to pursue some other remedies. Joe later sued Sam for False imprisonment. Explain the likely outcome.