I think everyone agrees - never say anything nasty to any potential customer, but if you do this mistake, at least don't do that publicly on a social network or anything that can be recorded.

On the other hand, there is no such thing as bad publicity, maybe it's their weird way to get recognition, by treating their customers like they owe them something.

After all I'm sure most of the readers will go to their website, just to see what it is, and even try their service.

So in the end, the bad customer service led to a blog post by the customer that was being badly treated, which might give them more traffic than if they were just nice, ironic.