Lightroom Piwigo PlugIn from Vladimir Vinogradsky is down

As I wrote in my original post, that site does not function. One can download an unregistered copy of the plugin and even pay $15 through PayPal, as I did on 2/28. However, Vinogradsky never sent the registration serial number. The serial number retrieval tool on his website does not function. The contact form on his website does not function. He never responds to his email alloyphoto@alloyphoto.com. And as I pointed out, he retracted his extension on the Adobe Exchange. 

I have requested a refund from PayPal, not because of the $15 but because I am hoping that PayPal has an alternate way to reach Vinogradsky. Perhaps he will send me my serial number. I also brought up the issue on the piwigo.org forum here: https://piwigo.org/forum/viewtopic.php?id=31782. The fr.piwigo.org forum contains a discussion (in French) of his site being down for a month or so in 2019 and then coming back to a functioning state.

Where is Vladimir? The fact that he updated the plugin in October suggests that he did not plan to abandon his entire site. Perhaps it was hacked. I still have hope that this is not permanent.