Why was the incident response not sent to the contact?
Oracle Service Cloud (OSvC), Message Templates
An auto response and agent response are sent at the same time, in an incident, but the recipient only receives the auto response. Both are saved as threads in the incident, but the agent response is not received.
Additional Message Template answers are mentioned here: Answer ID 5488: Popular answers about Message Templates
For more information about Message Template functionality, refer to the Overview: Message Templates section of online documentation. To access Oracle Service Cloud manuals and documentation online, refer to the Documentation for Oracle Service Cloud Products.