Appalling customer service
Compared to Australian banks, these Muppets idea of online is ridiculous. I'm fairly certain everyone is dropping their account and they are going under because their customer service is appalling. 
I've waited almost a week for a "phone specialist" to call me. Chased them up daily as soon as the online chat opened EU time. Was promised a call within 24 hours every time, but never did. I decided to just send the letter to close the account, and let that happen whenever someone at N26 decided to do some work. Funnily enough, then got a call at midnight, Australian time but there's just silence on their end! So since I'm half asleep I hang up. Got back on the chat, because how can I sleep now? And what do you know? Back to square one. Set up a new call with a new code and wait next to my phone 24 hours a day for God knows how long.

Edit to respond to N26 reply. They were made aware of my time zone from the first contact, when I expressed concern about what time I would be called "within a 24 hour period". When I was not called after 3 days I would have accepted a call at any time of day. When I finally spoke to a human being after 7 days, at 3am my time, I almost laughed out loud when they asked if I wanted them to call back at a better time. 

I also made an effort to access the chat daily at 5pm Aus Time, which is when business starts at N26, 7am EU time. So they had an entire business day, in their time zone, to call me. It still took 7 days and me telling them I wanted to close my account. Also, their system doesn't let them call while I'm on the chat. So my choice is waiting in radio silence for a call that will never come, or trying to get information and further delaying my call.