Login to your account via http://store.domainsifu.com/login.php
Upon successful login, you will be redirected back to home page, click on your name at top-right corner, select "My Account"
You should be redirected to your Customer Dashboard. Under “My Billing”, select “Pending Payments"
From this point onwards, the rest should be quite self-explanatory. Give us a shout if you need further assistance.