Amazon Japan rejected my bank verification for Sims 4 DLC purchase – any advice?

Hi,

I purchased digital DLC for The Sims 4 on Amazon Japan. Shortly after the purchase, my account was flagged and they requested bank verification.

I submitted an official bank statement. My name and billing address match my Amazon account exactly, and the payment was made by me.

Despite this, Amazon replied that they could not verify ownership of the payment method.

Has anyone experienced something similar? What would you recommend I do next?