Nintendo Switch OLED Payment Failures Across Multiple eShops, Unable to Buy Games

We recently bought two Nintendo Switch OLED consoles and naturally needed games to go with them. We initially bought a voucher to purchase games from the Japan eShop and continued buying games from there without any issues. However, since some games like Minecraft are cheaper outside Japan, we tried purchasing them from Argentina and South Africa eShops but encountered errors. Cards that worked perfectly in Japan didn't work on these other eShops. We decided to stick with the Japan eShop to avoid these issues, but now even the cards that previously worked are being declined. We’ve tried three different cards, and none of them are working, even on the Japan eShop. This is really frustrating—I'm unable to buy any games at all. Nintendo, please address this issue urgently!