Last friday we had a big snowstorm and the guy i hired showed up 5 1/2 hours late due to a breakdown on his truck. Then it broke down 3 more times during the remainder off the day. His plow would not go all the way down to the ground and would leave about three inches of snow everywhere.Due to this problem I had to bring other componies in to help out and pay them double since it was an emergency. I also lost 7 out of 9 clients because by the time the lots were clear it was very late in the day.At the end of the day this guy tells me I owe him $800 for the work he did. The way I see it I dont owe him anything because he didnt finish any of the jobs and I lost business because of him. What should I do?