Hi @Vincent Xu ,
We are sorry to hear you are facing this issue. It looks like your issue is similar to this post: https://learn.microsoft.com/en-us/answers/questions/1186444/acs-issues-acquiring-phone-number
Here is how you can resolve it:
"By default, Customers are limited to purchasing one phone number per tenant for Azure Communication Services through the Phone Numbers SDK or through the Azure Portal.
To request a new phone number, you need to go through the Manual process (special order numbers) by following the steps mentioned here special order
If your existing ACS resource has a valid phone number and if you have deleted it then you won't be able to acquire the new telephone number immediately, you need to wait to repurchase until the end of the billing cycle as explained here."
Please let us know if you have further questions.
-Grace