Originally Posted by AlphaWolf_HK
I haven't logged on to steam in ages but just recently I got an email from steam with a confirmation of an email address change without ever requesting one. So putting two and two together I tried to log in to steam and sure enough my password doesn't work.
The same thing happened to me early this year. It took a few emails to get it fixed but they worked on it pretty fast once I reported it. Good Luck.