Error multiple sites used

I bought the premium, for 1 site. Ive changed my site destination, and now i cant register with my license number, saying im using more then 1 sites.
I cant ulicense the previous destination for its not there anymore.

Ive been trying to reach you guys on email for over a week now, and i got no answer. Please respond.

https://wordpress.org/plugins/password-protect-wordpress/