I went to instagram! ... but there's a but

Dear people who use Instagram. I just joined in instagram by name finnishnightmaresmatti. The "finnishnightmares" username was already taken on instagram and the user of that account was not me despite the fact he/she's using my pictures.

:EDIT:

I got the situation handled and to prevent any further random copycats on Instagram, you'll find me behind the name finnishnightmaresofficial!