💡Amex One Annual Fee Policy, a lesser-known and "sorta/kinda" unwritten policy through which Plat. Charge holders pay only a single annual fee (the highest one) and the other cards in the account become free. 

Note, that this is different from the companion card policy.

If you hold a plat charge along with other cards and are paying an annual fee for those, call in or email and tell ask for the fees to be waived per this policy. 

You might need to get it escalated and push it a little since not a lot of agents are NOT aware of this.