When players were kicked from the eShop, they were given the error code 2811-7503, which according to Nintendo official support means you’re unable to access online features due to failure to connect to the service.
This is not exactly something players can fix, as it’s a server side issue.
Many players were met with an issue where their credit/debit account got a pending transaction, but Splatoon 2 remained unpurchased by their account as they were kicked before confirming the purchase. This is because Nintendo preemptively charges you with a pending transaction after you confirm your card information, before you confirm the purchase. However, it will not actually charge you unless the purchase is completed – and according to Nintendo’s support site, the pending transaction should go away within the next 1-3 days.
It’s understandable that it would be taking a long time purge all the pending transactions, considering just how many people tried and failed to buy Splatoon 2 last night. If after three days the pending transaction is still there I would recommend calling Nintendo’s support line (1 (800) 255-3700).
As for error 2811-7503, there doesn’t seem to be a problem with accessing the eShop or any network features anymore, so we can assume it’s all fixed on Nintendo’s end. So if you’re looking to buy Splatoon 2, you’re all clear.