fix: blacklist connection

services/data_service.py

@@ -456,7 +456,7 @@ class BlacklistDataService(BaseDataService):
         """Check if a user is blacklisted"""
         conn = self._get_connection()
         cursor = conn.cursor()
-        cursor.execute("SELECT * FROM blacklist WHERE user_id = ?", (user_id,))
+        cursor.execute("SELECT * FROM blacklist WHERE user_id = %s", (user_id,))
         blacklisted = cursor.fetchone() is not None
         conn.close()
         return blacklisted