1. You will receive a voucher / coupon like this ( login:password ) : kvnn68xxx:dczkmnyyy
2. Login into the account you want to extend. ( If you haven't account at http://dfiles.eu , you just need to sign up )
3. Open page http://dfiles.eu/gold/reselling_key.php
4. Enter to the field received info in the format login:password and send it.
5. The account becomes Gold.