Got following reply:
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I can understand your concern and I will be glad to go over this with you.
This particular offer is a promotion specifically designed for targeted new Cardmembers. We have various promotions throughout the year for loyal Cardmembers like you, which you would receive by mail or email from us. You can also find offers you are eligible for when you're logged in to your account.
I regret any inconvenience this matter may have caused you. Thank you for your Cardmembership and we look forward to continuing to serve you in the future.
Sincerely, Margaret Maggs Email Servicing Team American Express Interactive Services
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I give up.