The past couple of days have been rough for Nintendo. First we had the Nintendo eShop go offline, which subsequently resulted in Pokémon Bank and Poké Transporter being delayed. While many thought Nintendo was back on track, a lot of users are now getting error code 011-7510 when adding funds to the Nintendo eShop. Since this error is caused by losing connection to the access point, no money is added to your eShop account.
Despite the action failing and your account receiving no money, it seems your credit/debit card is still charged. Before you get too worried, this is a temporary hold-charge and according to “expert contributor” One-of-Three, it should go away in a day or two. In the event your charge is not refunded within a couple days, you should definitely contact Nintendo Customer Service by phone (1-800-255-3700) and get further assistance.
Hopefully this issue will be sorted out in a couple of days, but this is something you might want to keep in mind before adding funds to your account.