I am surprised at some of the responses that you have received. I can understand the basic concept that if someone's works fine they assume you just had bad luck by getting a defective unit, after all any company can make a mistake. But to imply that you are being unreasonable for giving up on the company after what you have experienced is a bit mystifying.
Even if we believe the excuse that you were given it would mean the following - here's a company making a device which manages the delivery of 40 amps and 240V of power between your house and your 30K+ car (even though Clarity only accepts 30 amps of this power). While making this device we are to believe that the assembler accidentally used a prototype handle even though the prototype warning is clearly stamped on the handle. When the device was QC'd somehow the text on the handle wasn't noticed. Likewise when the device was packaged it was again not noticed. Mistakes happen but this sequence of mistakes does not engender confidence in their process or in the person(s) who made these multiple mistakes. And by the way what about the missing dust cap? It's an attached item so it's not like it fell off, either this was yet another mistake in the assembly process, or it is proof that this was in fact a prototype unit that was not originally intended for sale, in spite of what you are now being told.
Made worse by the fact that the unit was sent as a replacement for the first unit which never worked from the beginning. The fact that the replacement immediately worked helps confirm that the problem was not user error or a problem with your electrical. It doesn't 100% confirm this, but naturally when the first item that you buy fails and the replacement works, it is compelling evidence that the first one was defective, or at best damaged in shipping.
After you experienced that the device that you purchased failed out of the box, and as a replacement you were sent either a prototype unit or a misassembled device, so you have decided to give up on the company. And you are being criticized for this? I just don't get it.
Now, I can imagine that this is a small company, and this is a somewhat niche market and profit margins are probably slim. So in general we root for these type of companies to succeed. They probably have some good technical people, but as often happens it is the other jobs like assembly, customer service etc. where the old adage "it's hard to find good help these days" can be a challenge especially if budgets are tight. Hopefully your problems are all the result of one less than conscientious employee who won't be there very long. But I can fully understand that you aren't willing to "ride it out" and hope for the best. While at the same time I understand why people who never had a problem with their unit are happy with their purchase. Fortunately for you Costco will not even blink when you go back to return it, their customer service people are the best.