Charge on different credit card

Since Nov 24, 2021 I have been charged $2.99 + interest for icloud. I only noticed today because this card is paid off. The card I have setup for subscriptions and payments with Apple is my Visa and ends in 6685. But this is happening with my America Express ending in 13002. I looked on my iPhone and see nowhere that American Express is listed. I want to have everything go through the Visa. Can you help?