Copyright infringement

You can't contact creators from what Adobe publishes. However, sometimes Google is your best friend. I, however, share the doubts of @Test Screen Name . You can't know if someone uses unlicensed items, except if you are an insider or if they are still watermarked. Even then, it may just be, that someone forgot to exchange the preview against the licensed item.

Adobe have a page for reporting copyright theft using DMCA law. Unfortunately, DMCA only allows the copyright holder to report. 

But anyway... how can you know there is no license for these images? There is no way for you to look them up.