BEWARE of this company!!!
BEWARE of this company!!!! I had an account and could no longer access my app and with it my account due to a software change. I received an email that I owed some small amount of €  which I transferred (again I could never check my account because I had no access) so I transferred a little more than they said I owed (it wasn't much so I just trusted that I must owe it).
So then I was suddenly told my account had been closed (which is no issue cos I wasn't using it anyways) but the best thing: I suddenly owe them several hundred € they said!!!!!
So how do we get from owing €66 - that were paid in full - to over €600 in under one month???????? despite not using the services or card anymore????
It is generally impossible to chat with support (I tried many many times in vain) and calling is the same story...nobody will ever attend. 
Stay far away from this bank. I have already warned all of my friends so nobody uses this bank anymore and people should close their accounts whilst they can. 
This company is the biggest fraud ever!!!!!! BEWARE!!!
Update after your reply: Well, guess what I had been in touch countless times and nothing got resolved. I received a mail asking me how I liked your customer service, after telling me you cannot help me out. Then I received another mail saying you are happy to tell me how I suddenly owe several hundred €, but you never told me you just announced you would be happy to if I reply that I agree that we talk about this via mail, I agreed, and then silence again. You people are terrible. I have told everyone to close their accounts asap, everyone that I had previously recommended you to.