A Non,
I'm sure you are already doing this, but make positively certain you are talking to the owner of the business. He is the one with the most to lose if he ends up in court, and in theory he cares most about his reputation (which you are kind enough to protect so far).
I would guess that you might also have bought this out of state to save on sales tax, so you would probably have to sue him where he lives. (I am way out of my expertise on that, so feel free to correct). If that is 350 miles away, it complicates things a little.
If you are on the west coast I can probably guess where you bought it. If I am correct, it might be worth a trip up to see the owner face to face. Not in a "in your face" type manner, but as a customer looking for resolution. It is easy to be brave on the phone or email (or to just ignore you), but something else when looking eyeball to eyeball with someone. You become a person with a problem, not just another mad long distance customer. Only do this if you have someone with you and you can control yourself and handle confrontation in a businesslike manner.
Dealing with the court system is expensive and slow. Sometimes it is necessary, but I would make every effort to resolve it out of court first. That might mean some compromise on your part regarding freight or something along those lines. If you have already had it out with this guy, he probably won't back down (the pride thing we all deal with) unless you give him a little wiggle room.
I'm a tractor guy, not a pyschologist...so I better stop. Good luck.