Hi @brian-hutchison ,
Thanks for the question! Are you trying to purchase more than one phone number? Is your subscription US-based?
Phone number availability is currently restricted to paid Azure subscriptions that have a billing address in the United States and Communication Services resources that have a US data location. Phone numbers cannot be acquired on trial accounts or using Azure free credits. For more information, visit the subscription eligibility section of this document.
For high-volume orders or in the event that your desired phone number is unavailable, complete this form and email it to firstname.lastname@example.org with a subject line beginning with "ACS Number Request:".
Please let us know if you have further questions.