Any loss due to a Mir program bug or malfunction will be restored. However, even if it can be assumed that the program bug or something caused this loss, sometimes we cannot restore it, if it is not certified by our game logs. Uncertified restoration can affect future game management or may harm equality between users.
General F.A.Q.
Game Progress
Technical Questions
About Item
Concerning account and ID.
Restoration of removed character
Illegal program usage
Program bug of 'Mir' 
Trouble during normal game status