OP, sorry for your ordeal. It is not surprising the company has lost a customer. One trial like yours will do it. Having some experience from the company side of the equation, (not in Emotiva), I have seen good and bad practices and execution of Customer Service and the call-takers. Not making excuses, but there can be a number of reasons for such a poor response that range all the way from a particular call-taker having a bad day to an internal IT/system problem to a company policy that is less than focused on after-the-sale support.
Usually when there are mixed reviews, (some people say it is great, some say dog lousy), it is an indication that a company wants to do right, but is having trouble with resources and execution. None of that matters to the customer. The company who recognizes the problem, identifies the cause and fixes it will survive. Those who don't, won't.
Adam was making a little inside joke when he referenced being "more abrasive" to the call-taker. You can see in the rest of his post that he does not really do that, and he's right. It is rarely fruitful. Remember, these call-takers make their living talking to unhappy customers. It is the rare gem of an employee that does not become tainted in time... and even more rare to find one who is actually spurred to helpful action because of your aggression.
If you assume the company mgmt does indeed want to do right, the most helpful course in an experience like yours is to escalate up the chain and find one of these people. Sometimes you can simply ask the call-taker to speak to their supervisor. Sometimes you need to get to the supervisor's supervisor. Sometimes you can do some web searches and find contact info for an exec in the company. Execs gets customer complaints all the time, and have a regular process to forward them to the execution team. And believe me when I tell you every large company has mid and low level mgmt who garner no respect by virtue of their own worth, so relish in the opportunity to throw their weight around and tell other mgrs/engineers "You must take care of this NOW because it comes straight from Mr/Mrs Exec".
Old timers who "grew up" with the execs LOVE to hear this from some useless whippersnapper, regardless of his/her level. I would usually tell the punk something like, (I'm busy. You can tell Mr/Mrs Exec I said to kiss my a**". Of course I would take care of the problem, and send a private note to the exec letting him/her know it was done. But in the meantime, I got to watch the jerk have hissy fits. But the point is, the problem was fixed, always, if possible, when it came down from an exec.
Can't say what the cause of your runaround was, but from what I hear, it sounds like Emotiva wants to do right. While it shouldn't be your responsibility, sometimes finding the right contact in the company is the path of least resistance.