First, please log into your dashboard. (For steps on how to log in, please check out this article)
Next, click on Account Settings at the top right.
Next, click on the Billing tab. Click "Add New Payment Method".
Next you'll enter the new billing information and click "Add new payment method".
To select the new payment method as the primary on the account, simply click on the "Locations" tab, click "Edit Billing Details" and select the new account and Update.
For information on finding your past invoices, please check out this article.
For questions regarding your current or past due bill, please contact Matt at firstname.lastname@example.org or you can call 844-552-2873 and select #3.