Below is an overview of how the system selects which Twilio Outbound Number to use for a contact, according to various scenarios:
If the contact is assigned to a user, and the assigned user has an inbound Twilio number selected, the system will always default to the inbound Twilio number.
If the contact is assigned to a user, and the assigned user does not have an inbound Twilio number, the system will use the Default outbound number selected.
If the contact is not assigned, the system will use Default outbound.
If the contact will be contacted again, the system will default to whatever number was previously used to contact them. This rule applies unless they have since been assigned to a user and the user has a different inbound Twilio selected.