Has Runningman gone out of business? When I try to purchase a license, it directs me to a dummy WordPress site with no content. Did they close, or just let their URL registration lapse?
Yes, it appears that Runningman has gone out of business. When I access the website, I get a front page from the standard theme installed on Wordpress with no content displayed.
This also means it's currently impossible to acquire a license or activate the one you have for Duplicate Image Finder. The only thing you can do right now is to pick an alternative.