If you have more than one phone number associated with your account, know that only one at a time can be administered in the Telephony section.
The number that is active is identified on the right of the title of the Telephony section in the menu
and at the top of each page of the Telephony section.
Note that from the Home page, you can get a summary for each of your phone numbers. By clicking on one of them, you can change the active number and simultaneously jump to the Telephony section.