Nintendo has announced that the limited eShop that's available in Latin America and other Caribbean countries is going to close on July 31st, 2020. You can see the official (Google translated) statement below.

In certain Latin American and Caribbean countries, the limited version of Nintendo eShop for Wii U and Nintendo 3DS consoles offered some basic functions such as the ability to redeem codes. This limited version of the Nintendo eShop will close from July 31, 2020 and users in the affected regions will not be able to access it to redeem download codes, download programs again or update their programs. So we urge users to take these actions before closing. Also, those programs that require the limited version of Nintendo eShop to operate may stop working. Take into account that Mexico and Brazil will not be affected. Thank you all for using Nintendo eShop and for being great Nintendo fans.

For those who have codes that aren't redeemed yet, or have any other questions on the matter, the official FAQ for this closure can be found here.

Thanks to ThatWaluigiDude for the heads up!