I wouldn't trust Commbank with their refusal. They tried that with me and explained it was part of a directive from the Government. I contacted Fair Trade and Fair Trade told me it as utter rubbish. So when I rang back, the Commbank staff started my chargeback. Please note you must try to resolve...

Hi David, I have noticed when using the AMEX online site you normally pay a premium. Its is best to use up the credits then forget about AMEX's site for the remaining annual period. This also includes hotels as they are marked up when comparing to other websites.