If you want to update the billing address you have on file just follow these steps:
Log in to your customer’s portal: https://billing.stablehost.com/clientarea.php
Go to ‘Hello <Your Name>! ‘ and click on ‘Edit Account Details’.
On the right-hand column, you'll see all the input fields for your billing address, make the necessary changes.
On the left-hand column, there is a field called "Default Billing Contact". Set it to "Use Default Contact".
Click on ‘Save Changes’.