Trouble with image 201827095

Hi,

I downloaded this banner background image and noticed that there are horizontal line artifacts that are extremely difficult to erase without having to go through a lot of trouble.  I noticed them first when i bumped up the contrast to create a displacement map.  At any decent size these lines are visible and are clearly not supposed to be part of the image.

If i had to guess, I'd say this was a vector graphic at one point that was saved as jpeg and the author left the artifact in by accident.  Anyway, I want to report it and if possible be refunded the spent credit for the image.