My two cents:
Without trying to be reductive, Virgin's issues with point posting is well documented on AFF. Not that that's an excuse by any means, but it should certainly serve as a buffer against any over-emotional reactions. If the way I read the original post (after editing, mind you) translates even closely to how the phone conversation went down, I would have hung up too. Inarticulate, irate and demanding = more than these people are paid to tolerate. The personal jabs such as "pathetic" and "not deserving of your position" are way, way too far over the line.
"The customer is always right" isn't a blanket fact, it's a philosophy taught to employees to encourage strong customer service. Boy, I wish it stayed a back-of-house term. Unfortunately, there are times where you don't have the immediate means or resources to fully sate a customer. There are even times where the customers is plain wrong. Customers who brandish this line about are most often in a one-track state of mind and tend to use it as an excuse for unreasonable expectations which, when not met, devolve into unreasonable behaviour.
Hopefully this issue can be sorted amicably for you, but I also hope that you learn from it too.