Licent banned?!

I haven't played my diablo 3 game in almost 5 months now. Then suddently I get this email:

Diablo III - License Banned NOTICE OF LICENCE TERMINATION Offense: Use of Bots or Third-Party Automation SoftwareBlizzard Entertainment has terminated this Diablo III license after identifying the usage of bots or other cheat software.

Help me anyone?

EDIT: I can't log in, im supposed to enter this authenticator code, and I have not bought one, or used it before. I tryied download the app and use the code there, but it did not work.