We purchase a phone number to connect to your account through the phone company we are connected with. They have new numbers available for use based on demand. There is no way to look for a specific number. However, the list does update every few hours.
If you cannot find a number or one is not available please have some patience as you refresh and check back every day. Generally it does not take long and a number can be found fairly quickly. Some remote areas may experience a longer wait. Reach out to support and we can extend your trial until a number can be selected.