Unsubscribing from email with Air Berlin

For quite some time, I've been receiving email newsletters from Air Berlin at least two or three times per month. I've often tried clicking the direct-unsubscribe link, but this always led me to a login prompt at a confusing website:

So to unsubscribe from their emails I'd need to first go through the password recovery process (since I have no idea what my login details are) and then I'd be faced with figuring out where one manages email subscriptions. (And judging from the UX of that login screen, that wouldn't be an easy task.)

Today I decided to do something about it. I checked and sure enough there's a Twitter account sitting at @airberlin, and so I sent them a message. I think you'll find the ensuing conversation to be both entertaining and perhaps sad at the same time.