diff --git a/api/services/telephony/providers/cloudonix/provider.py b/api/services/telephony/providers/cloudonix/provider.py
index 950cd050..31b84fb6 100644
--- a/api/services/telephony/providers/cloudonix/provider.py
+++ b/api/services/telephony/providers/cloudonix/provider.py
@@ -388,13 +388,16 @@ class CloudonixProvider(TelephonyProvider):
 
         disposition = data.get("disposition") or ""
         session = data.get("session")
+        billsec = data.get("billsec")
 
         return {
             "call_id": session.get("token") if isinstance(session, dict) else "",
             "status": disposition_map.get(disposition.upper(), disposition.lower()),
             "from_number": data.get("from"),
             "to_number": data.get("to"),
-            "duration": str(data.get("billsec") or data.get("duration") or 0),
+            "duration": str(
+                billsec if billsec is not None else (data.get("duration") or 0)
+            ),
             "extra": data,
         }
 
diff --git a/api/tests/telephony/cloudonix/test_routes.py b/api/tests/telephony/cloudonix/test_routes.py
index a9b288b1..31cf220a 100644
--- a/api/tests/telephony/cloudonix/test_routes.py
+++ b/api/tests/telephony/cloudonix/test_routes.py
@@ -118,3 +118,17 @@ def test_parse_cloudonix_cdr_maps_disposition_and_session_token():
     assert req["call_id"] == "abc123"
     assert req["status"] == TelephonyCallStatus.BUSY
     assert req["duration"] == "12"
+
+
+def test_parse_cloudonix_cdr_preserves_zero_billsec():
+    """A zero billed duration must not fall back to total call duration."""
+    req = CloudonixProvider.parse_cdr_status_callback(
+        {
+            "session": {"token": "abc123"},
+            "disposition": "ANSWER",
+            "billsec": 0,
+            "duration": 42,
+        }
+    )
+
+    assert req["duration"] == "0"
diff --git a/api/tests/test_pipecat_engine_end_call.py b/api/tests/test_pipecat_engine_end_call.py
index 6f1f7c31..b927369b 100644
--- a/api/tests/test_pipecat_engine_end_call.py
+++ b/api/tests/test_pipecat_engine_end_call.py
@@ -834,9 +834,7 @@ class TestEndCallRaceConditions:
                         EndTaskReason.USER_HANGUP.value, abort_immediately=True
                     )
 
-                await asyncio.gather(
-                    run_pipeline(), initialize_and_race_disconnect()
-                )
+                await asyncio.gather(run_pipeline(), initialize_and_race_disconnect())
 
         # Verify disconnect was attempted
         assert disconnect_called, "Disconnect should have been called"
diff --git a/sdk/python/src/dograh_sdk/_generated_models.py b/sdk/python/src/dograh_sdk/_generated_models.py
index cd56b905..090eee70 100644
--- a/sdk/python/src/dograh_sdk/_generated_models.py
+++ b/sdk/python/src/dograh_sdk/_generated_models.py
@@ -1,6 +1,6 @@
 # generated by datamodel-codegen:
-#   filename:  dograh-openapi-XXXXXX.json.rRr9IUrKFk
-#   timestamp: 2026-06-23T13:02:10+00:00
+#   filename:  dograh-openapi-XXXXXX.json.YWer7ilGLp
+#   timestamp: 2026-06-24T16:36:26+00:00
 
 from __future__ import annotations