My son was playing Minecraft via the Switch yesterday.
Today it had a software update and wiped his marketplace purchases and zeroed out his Minecoins. Don't ask me how, I have no idea.
We purchased Minecoins via the Nintendo eShop on 3/6/2021 Screen shoot included.
This was enough to buy two map packs; "Jurassic World" and "Ancient Dungeons".
He is now not able to create OR EVEN access previous world saves that he was using, but the packs still show up as an option under his "Create New World", but are now locked.
It also now asks for a Microsoft account to work. (On a Nintendo device?)

Please just help get back my kid's map packs.