To see if you're eligible, log in to your AmEx account, then scroll down to "AmEx Offers and Benefits". If the offer is there, just click on "Add to Card." It says may take up to 90 days from 9/5/21 for the credit to post, but past experience with similar offers is they post very fast. Good luck.
"Enrollment limited. Must first add offer to Card and then use same Card to redeem. Only U.S.-issued American Express® Cards are eligible. Limit 1 enrolled Card per Card Member across all American Express offer channels. Your enrollment of an eligible American Express Card for this offer extends only to that Card. Offer valid for purchases made directly with Telecharge only through telecharge.com or by calling 1-800-447-7400. Not valid for purchases made in-person at the box office or at theaters. Excludes all purchases made through partners, third parties, or affiliate sites with links to/from telecharge.com. Offer is non-transferable. Limit of 1 statement credit per Card Member. Any benefit earned from this offer is in addition to the rewards (i.e. Membership Rewards or cash back) earned as part of your existing Card benefits, Statement credit will appear on your billing statement within 90 days after 9/5/2021, provided that American Express receives information from the merchant about your qualifying purchase."