diff --git a/video-gen-api/app/services/payment.py b/video-gen-api/app/services/payment.py
index 5c08b81f..74732dc9 100644
--- a/video-gen-api/app/services/payment.py
+++ b/video-gen-api/app/services/payment.py
@@ -1,7 +1,6 @@
 import logging
 import os
 from datetime import datetime, timedelta
-from logging.handlers import TimedRotatingFileHandler
 
 from sqlalchemy import select
 from sqlalchemy.ext.asyncio import AsyncSession
@@ -13,28 +12,53 @@ from app.services.credits import add_credits
 from app.utils.id_gen import generate_id, generate_order_no
 
 # ---------------------------------------------------------------------------
-# Payment logger → log/payment/YYYY-MM-DD.log (one file per day, keep 30 days)
+# Payment logger → log/payment/YYYY-MM-DD.log (one file per day, no cleanup)
 # ---------------------------------------------------------------------------
+import time as _time
+
 logger = logging.getLogger("payment")
 logger.setLevel(logging.INFO)
 
 _log_dir = os.path.join(os.path.dirname(os.path.dirname(os.path.dirname(__file__))), "log", "payment")
 os.makedirs(_log_dir, exist_ok=True)
 
-_file_handler = TimedRotatingFileHandler(
-    os.path.join(_log_dir, "payment.log"),
-    when="midnight",
-    interval=1,
-    backupCount=0,
-    encoding="utf-8",
-    utc=False,
-)
-_file_handler.suffix = "%Y-%m-%d"
-_file_handler.setFormatter(logging.Formatter(
+
+class DailyFileHandler(logging.FileHandler):
+    """Write to a file named by date, e.g. log/payment/2026-06-10.log"""
+
+    def __init__(self, directory, encoding="utf-8"):
+        self._directory = directory
+        self._current_date = ""
+        self._file_handler = None
+        super().__init__(self._make_path(), mode="a", encoding=encoding, delay=False)
+
+    def _make_path(self):
+        date_str = _time.strftime("%Y-%m-%d")
+        self._current_date = date_str
+        return os.path.join(self._directory, f"{date_str}.log")
+
+    def emit(self, record):
+        date_str = _time.strftime("%Y-%m-%d")
+        if date_str != self._current_date:
+            # Day rolled over — switch to a new file
+            if self._file_handler:
+                self._file_handler.close()
+            self.baseFilename = self._make_path()
+            self._file_handler = logging.FileHandler(
+                self.baseFilename, mode="a", encoding=self.encoding
+            )
+            self._file_handler.setFormatter(self.formatter)
+            self._current_date = date_str
+            self.stream = self._file_handler.stream
+        super().emit(record)
+
+
+_handler = DailyFileHandler(_log_dir)
+_handler.setFormatter(logging.Formatter(
     "[%(asctime)s] %(levelname)s %(message)s", datefmt="%Y-%m-%d %H:%M:%S"
 ))
 if not logger.handlers:
-    logger.addHandler(_file_handler)
+    logger.addHandler(_handler)
 
 # Orders pending payment for longer than this are auto-cancelled
 ORDER_EXPIRE_MINUTES = 5