All OnSIP services are billed in advance. You have two separate ongoing balances as an OnSIP customer:

• Plans: Monthly charges for your application services or per-user charges.
• PSTN (Prepaid): Pay-as-you-go calling credits and phone number charges (per number) as well as toll-free inbound and international dialing.

In the Web App you can view your Plan and Calling Credits information by navigating to your profile icon in the top right corner.  From the drop down select Accounts and Payments. 

From the next view you'll be able to select Plan Overview to see your monthly billing plan or Calling Credits to view your available calling credits.

Note: Your pre-paid calling credits must remain in the positive to make and receive calls to / from the PSTN (traditional 10-digit numbers).