while browsing images I accidentally clicked on "license" button on random image on screen - and I did'nt find any way how to unlicense it, as it's not picture I'm interested in. I deleted it from my library, thinking it would solve my problem, but now I still have "-1 asset" from what I had - is there way to fix that? Maybe license button should really have some confirmation needed before actually licensing it for the user.
As you figured out already, it is not possible to return a licensed product, but Adobe may be give you a replacement credit. For credits you will need to contact Customer Care. You can begin a secure chat session by clicking on the chat icon on the bottom right corner of this link: https://helpx.adobe.com/contact.html
Note: Pop-up blockers need to be disabled and cookies need be accepted for the chat to work. You may type in AGENT to skip through the automated assistant and reach a real person.
I hope this helps.