I am also new to stock and find it so annoying how easy it is to licence an image! I just wanted to save image 106531423 to my library so I could proof to a client and it has licence it! The save preview to CC library didn't to be there??!!!!
Branching into a new discussion
I apologize for the troubles that you've faced with the Stock website but unfortunately there is no way to unlicense an image if it has been licensed once.
But I have added 1 license to your account so that you can use it against this image.
Please see Stock FAQ: How to license an image with Adobe Stock? and Stock FAQ: How does Adobe Stock integrate with Creative Cloud apps? to know more about the license workflow.
Hope that helps!