1) Delete the registered credit card from the Nintendo Account following these procedure :
https://www.nintendo.co.uk/Support/...ormation-from-a-Nintendo-Account-1462905.html
Try again to purchase the game and enter the information manually. Did it work ? If not, follow the remaining steps.
2) Clean the cache of the console :
1.Select System Settings from the HOME Menu.
2.Scroll down and select System.
3.Scroll down again and select Formatting Options.
4.Select Clear Cache.
5.Select the user you would like to clear the cache for, then slect Reset to confirm.
3) If a microSD card is inserted into the console, power the console off, remove the microSD card and then power the console back on and try to access Nintendo eShop again.
After this is done, whether the issue is resolved or not, power the console off, and re-insert the microSD card.
Did it work ?
If not, the error code you're receiving often occurs when a payment fails and becomes "trapped" in the system.
In most cases this issue will become resolved when the payment expires from the system. This typically takes 30 days from the most recent payment attempt.
In the meanwhile we recommend that you delete any credit card details currently saved in the system and ensure that your Switch consoles is running on the latest software.
As a temporary solution we suggest you attempt to make the payment using PayPal.