Deregister my purchase code Accidentally


I´ve deregistered the purchase code for my site. How can I fixed? I don´t want to purchase the license again.
I copy the text from my dashboard: This installation has been deregistered and can’t be registered again with this purchase code. Please purchase an additional copy of theme in order to get a new valid activation key for this installation.

Thank you

If it’s the same domain name, just contact the item author and explain the situation. They should help to fix the problem