diff --git a/backend/services/redis_service.py b/backend/services/redis_service.py
index 6682a4e..c138488 100644
--- a/backend/services/redis_service.py
+++ b/backend/services/redis_service.py
@@ -30,7 +30,7 @@ def save_chat(user_id: str, session_id: str, message: dict):
     r.rpush(key, json.dumps(enriched))
     r.expire(key, DEFAULT_TTL_SECONDS)  # rinnova TTL history
     _update_session_stats(user_id, session_id)
-    _refresh_ttl(user_id, session_id)  # rinnova TTL meta e indice
+    refresh_session_ttl(user_id, session_id)  # rinnova TTL meta e indice
 
 
 def get_chat(user_id: str, session_id: str, limit: Optional[int] = None):
@@ -49,7 +49,7 @@ def clear_chat(user_id: str, session_id: str):
     key = f"chatHistory:{user_id}:{session_id}"
     r.delete(key)
     _update_session_stats(user_id, session_id, reset=True)
-    _refresh_ttl(user_id, session_id)
+    refresh_session_ttl(user_id, session_id)
 
 
 # -------------------------
@@ -101,7 +101,7 @@ def update_session_meta(user_id: str, session_id: str, **updates) -> Optional[di
         return None
     meta.update(updates)
     r.set(f"chatSession:{user_id}:{session_id}", json.dumps(meta), ex=DEFAULT_TTL_SECONDS)
-    _refresh_ttl(user_id, session_id)
+    refresh_session_ttl(user_id, session_id)
     return meta