deal with SUCCESSFUL pinpoint receipts

app/celery/process_pinpoint_receipts_tasks.py

@@ -53,6 +53,10 @@ def process_pinpoint_results(self, response):
         provider_response = receipt["messageStatusDescription"]
 
         notification_status = determine_pinpoint_status(status, provider_response)
+
+        if notification_status == NOTIFICATION_SENT:
+            return  # we don't want to update the status to sent if it's already sent
+
         if not notification_status:
             current_app.logger.warning(f"unhandled provider response for reference {reference}, received '{provider_response}'")
             notification_status = NOTIFICATION_TECHNICAL_FAILURE  # revert to tech failure by default
@@ -125,6 +129,8 @@ def determine_pinpoint_status(status: str, provider_response: str) -> Union[str,
 
     if status == "DELIVERED":
         return NOTIFICATION_DELIVERED
+    elif status == "SUCCESSFUL":  # carrier has accepted the message but it hasn't gone to the phone yet
+        return NOTIFICATION_SENT
 
     response_lower = provider_response.lower()