I'll try to get in contact with them again first, give them a chance to delete it themself. If they get many more downloads I will.

report the person that stole your creation then

I noticed. They don't seem to care, however. Neither does anyone downloading it.

someone is trying to steal your creation

I've actually just made the enemies unable to hear, but as that typically wasn't something causing detection for me anyway, I figured using it for the silenced rifle would work fine without making the mode play strangely.