Thank you for writing to us at the Star Alliance Help Desk.
By being a Star Alliance Gold member, and depending on the ticketing rules of your journey, you are allowed to check-in an additional 20kg (44 pounds) or one additional piece of luggage, which means you can check in three bags instead of two.
If you feel that you are eligible kindly contact us so that we will post a complaint against airline.
Therefore, for specific information, you will need to get in touch with the operating carrier directly.
http://www.staralliance.com/en/contacts
We hope this information is of help.
Thanks again for contacting us.
Regards,
Star Alliance Help Desk
STAR ALLIANCE
THE WAY THE EARTH CONNECTS
www.staralliance.com