This is Sean with Urban Airship Technical Support.
You should be able to see your payment history by clicking on the user icon in the top left of the Urban Airship Dashboard and selecting Account Info. On the Account Info page, you should see a pane titled Plan & Payment Details. Click the Payment History link in this pane to see your past payments.
See our documentation on Managing Your Account for more information.
Please let me know if you have any other questions or concerns.
Urban Airship Technical Support