Let me first make this abundantly clear; I'm not supporting their actions in any way shape or form.
That having been said, I own an internet based company, and I know that it costs money to do business. I love companies like 6Ave because they make it easier for me to to business, and I also hate them because they jade consumers against online purchases in the first place. But here's what I know from experience:
When you sacrifice margin to make a sale, you also sacrifice service. You can't afford to put the systems in place that need to be there. You can't afford to hire ethical salespeople with integrity and voracity. That's no excuse, but it is a fact of the matter, and that's why companies like Crutchfield exist.
Just to be clear, I purchased my Z1 from 6Ave as well, and while I still haven't received my ND-BT1, I haven't been charged for it yet either. Again, I'm not trying to defend them, I'm just saying that we all have choices as a customer, and anyone in business knows there is no such thing as a free lunch. You can't expect to buy a Z1 for less than many dealers pay and still get the best customer service possible, it just doesn't add up. That doesn't mean that you should be lied to, or that they shouldn't back up their return policy, but I have a feeling they're going to issue you an RMA, and immediately going to a charge-back doesn't always make for the best way to resolve a situation.
Sorry if you feel like I'm attacking you, or like I don't believe you. I think it's just prudent for consumers to take everything into consideration.
BTW, are you a wakeboarder, or just a boat owner?