I had this happen to me before. I suspect it was from someone else trying to log in to my account. All I had to do was go through a password reset/auth codes and it was unlocked. I tried logging in just now and it only asks for an auth code.
MF question: Anyone care to clarify whether the rolls you get on an item/quality of rolls is affected by MF, or only your % chance of getting a certain color of an item. Basically, are the rolls on any given item and the quality of them completely random?
100% MF doubles your chance of rolling a blue, legendary, rare etc. It has no effect on the rolls of the item.