It's beside the point, but most folks here are assuming the bow was damaged during the weight reduction process. In fact, we have no way of knowing that. The bowyer might have accidentally run over it with his truck, of set it down on the table saw, which just happened to be running at the time. Who knows.
He agreed to take 5# of weight off. That's not a lot of weight for a 74# bow. Before starting the job, he no doubt had an opportunity to inspect it and could have declined the job if the bow looked suspect.
IMO, he broke your bow and owes you a replacement or your purchase price. However, if you don't have an agreement in writing, there's not much you can do about it.