Kindly go To login area as per below lin
https://www.signdomains.com/clientarea.php
Kindly login with your registered mail id and password, if you don't have password just click on forget password for get the password on your mail
https://www.signdomains.com/pwreset.php
After login in client area got domain and select your domain and years,
add to cart and click on checkout and make the payment,
Kindly after make the payment send one mail on supportdesk@signdomains.com for fast domain renewal process