As an artist, stuff like this is both flattering (they liked my design enough to steal it), but incredibly frustrating. I am trying to make a living after all.
If you are a graphic artist, especially if your work features any pop culture references, maybe check to see if some of your stuff may have found its way on there... When researching it, I saw some designs that looked very familiar. I am waiting for a response after submitting a DMCA takedown request.