Check
this website out (the BLW bans page) and search for your Steam username up the top right. I tried to find it for you but "DemonicSpy" is returning no results so I assume your username is different. It'll show you how long you were banned for, who banned you, why you were banned as well as a bunch of other information.
Also, if you'd like to make a ban appeal, go to
this section (punishment appeals) and post an appeal there.