The problem here isn't that a mistake occurred. Mistakes do happen and on occasion its something you'll have to deal with. Most reasonable people don't blow up over minor errors.

The problem here is that the company in question apparently offers no realistic means of providing customer support. When you're providing a free service, I can understand not wanting to spend money offering some form of customer service.

But when you're charging money for a service, not having any customer service that can help you isn't nice at all, to put it mildly.