Amazon Japan must have stepped up their game in the last month. I used the same card/address combo for a 500 yen eShop account earlier this month for Kamiko and didn't have a problem.
It immediately bumped me to the verification phase for Mario Kart 8 Deluxe. Do not use Apple Store Tokyo as your verification address anymore, I guess.
Anyway. I just wrote Amazon Japan with "Cancel" in both English and Japanese because the page said I could do so during the verification phase. My debit account hasn't been touched.
The digital order did allow me to change payment options. I still have my Google Wallet debit card. The card is a dud and will always reject due to its zero balance and the fact Google discontinued the card.
Ended up switching payments, deleting my original payment, and not worry about it failing or not because the payment likely won't go through regardless now.