It might be because their main business isn't audio ...it's making electrical parts for business. They may not care about a few dollars here and there when they deal with large contracts.
There's the example you asked for - you're speculating the company does not care about customers who make small orders.
Ok, you acquired some cables and need different connectors on them. The fact that you bought them and now need different plugs does not sound like the fault of the vendor. You tried to place an order and had a problem. Sounds like you talked with two different people and each didn't know what you told the other and your order fell through the cracks. Now, because the second person didn't apologize to you and offer to send you free plugs, you *feel* insulted and got your undies in a bundle. Maybe thats how you feel. Sure maybe anyone might experience a little frustration. But I don't see where it warrants attempting to smear the company anonymously.
The world isn't perfect everyday. But this does not sound like you've been egregiously ripped off or received false promises. Does your thirty dollar order mix-up warrant an anonymous attack in a public place? I haven't read that someone actually said anything to you that might be considered an insult. And we only know one side of the story.
Imagine an equally anonymous response using your same logic: "well I've heard they have great customer service and you musta been rude to Dawn and affronted her dignity to get that kind of response". Just speculation, ya know - how would that anonymous message feel to you?
What do you want? Do you want the self-satisfaction of whacking at them with no liability to yourself? Maybe accrue a little sympathy while getting other anonymous posters to pile on? (As in Ctb's 'do you still beat your wife?' message.) Do you want to harm their business or teach them a lesson? Or do you want the banana plugs? There is no evidence of anyone acting in bad faith - this sounds like a simple mistake on someone's part.
I'll suggest it is far more effective to contact the manufacturer and calmly explain the situation - maybe send them an e-mail so you have something to reference. Or maybe it is simpler to just start over and pretend you are making a new order.