In case you need to check the information about your Newoldstamp subscription, like what package is applied to your account, how many signatures you have already used, and what is the next payment date, please go to your Account Settings.
On the right side of the screen you will see brief information about your subscription:
In case you need to upgrade your current subscription plan, please use the Upgrade plan and follow the instructions listed here.
In case you need to review the payment history please navigate to the Billing settings tab.