Hey there. So I wanted to remove my Nintendo ID from my 3DS. I've linked it with my Wii U already. It said, if I delete it off of my 3DS, it'll delete the ID on my Wii U as well. Which I didn't want. My only option was to format the system memory. I wasn't paying very close attention, and I went through with it. (This is a lesson for future reference I guess). After it was done, it was back to factory default. What I didn't know, was that all the content of my SD card would be gone as well. So I lost a little over 100$ in eShop games and content. Now, I'm not sure whether there's a way to get the lost content back or not, but if it helps, my Club Nintendo history still shows all the games I've purchased and registered. So I have proof of what I had. I'd appreciate any help, even if there's not a way. 
Thanks.