Activating my Premium License

We have purchased the Premium Single site license for mailpoet plugin but its showing the message “domain already attached to another licence that you don’t own” on the Licence activation page “http://www.mailpoet.com/account/licences/”

If the domain is already attached to another licence the plugin should work on our WordPress Dashboard, but on premium Tab of Mailpoet on dashboard “wp-admin/admin.php?page=wysija_premium” On clicking of button “Already paid, Click to activate”

Shows the message of “Your Premium licence has expired.”

https://wordpress.org/plugins/wysija-newsletters/