Nexon's negligence.

Any reports on account loss will most likely get this response that Nexon replied someone with on BBB;

As for the compensation that may be available, please keep in mind that this character delete was not due to an issue in security on the part of Nexon America. Account security is the responsibility of the account creator, and the security of the email address registered to the account as well.

Minus the character deletion part. Not that I'm against this, I just felt like pointing out that they'll most likely just dismiss it.

Response taken from here.