title: Not able to get Azure Billing Account Id
body: <p>I need to get Usage Details at Billing Account Scope for that firstly I used <a href="https://docs.microsoft.com/en-us/rest/api/billing/2019-10-01-preview/billingaccounts/list" rel="noreferrer">this API</a> but It returns an empty value. I used the Bearer Access token for hitting this API.Is anything other than this am I missed?</p>
  <p><a href="https://i.stack.imgur.com/a17fU.png" rel="noreferrer">Postman Request attached as screenshot</a></p>
  <p><a href="https://i.stack.imgur.com/FX373.png" rel="noreferrer"><img src="https://i.stack.imgur.com/FX373.png" alt="Postman Request attached as screenshot" /></a></p>