Irritating, but what was really dishonorable here? The guy saw that the deal was going to be better for you than for him, and decided not to go through with it. Dishonorable would have been him asking you to ship first, and then never sending his knives, and in effect, stealing yours.
Sure, the guy could have done all that before saying he'd do the deal. But hey, no deal was actually struck, so...?