Quoting some important info from their website:

What happened?

Hackers gained access to one of our servers. We discovered the break-in and interrupted it instantly. The security gap through which the hackers gained access was closed immediately. At the same time we reported this incident to the police. Further investigations are underway. Unfortunately, the traces of the well-concealed hackers currently disperse abroad. That is why the expenditure of the German law enforcement agency was significantly increased and the clearing up has become more difficult.

Which data were stolen?

The stolen pieces of information are data of addresses such as name and e-mail address. Billing information (e.g. credit card information or banking information) is definitely not affected, because our shop service contractors are concerned with this data and it is not stored on our system.
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