delete https://api.phone.com/v4/accounts//extensions//messages/
Phone.com’s standard phone service lets you send and receive SMS/MMS messages using your Phone.com numbers. The Phone.com API extends this functionality, letting you send SMS/MMS messages from your application (through your phone number and our API server) to your users. You can also use the API to retrieve the history of SMS/MMS sent from / delivered to your account.
This service is used to delete a message for extension