BBB is worthless. For the one customer in 10,000 that actually checks these things it's okay, and for the merchant who pays $500 a year for the sticker, it's a nice advert . . . that's about it.
First, send a letter rejecting the goods and explaining why they are unsuitable (reference the the agreement or understood work order as best as you can), then you don't pay the guy. Advise him that he can sue you for the work, but that you will counter-claim for your lost goods. If you do end up in your local version of small claims court, be prepared. Document what you paid for the belt, further document what it would cost to replace the belt.
Be prepared to demonstrate WHY the work is substandard and why the belt is useless.
At the end of the day, I wouldn't expect much success (the adequacy of performance is usually an objective standard - so if you're being picky, you're screwed), but if you're a man of principle . . .
The theme of your argument is this is an expensive luxury good (see what I paid), and an expensive artisan, the standards should be much higher. I know what I wanted, I showed him pictures, here are listings of these types of bracelets, it is incumbent on him to document the order, not me . . . it's his business, not mine. In essence, don't blame me for sending my wrong order back if the waiter failed to write it own.
The historical case that all you legal eagles are hinting around is Jacobs & Youngs v. Kent, or the "Reading Pipe" case. This should be required reading for any exacting and litigious customer, even though it carries virtually no weight these days.
There is no requirement that this particular contract be in writing, but it certainly makes things easier in most (but not all) cases.