Tropo places a few restrictions on newly-created accounts. Verifying your identity will remove those restrictions.
Verifying your account is a two step process. The first step is to add a payment method to your account. Tropo will charge a $10 deposit to verify that the payment method is valid and the payment account is active. This $10 deposit will be credited to your future Production application usage. Testing a Tropo application in Development mode will not affect your deposit. The second step is to contact support and provide your landline or mobile phone number. Tropo will make an automated telephone call to this number to verify that the number is active and that you answer it. Full details about how to get your account verified are available in the article