Other Games I lost Butdata from my 3ds help

Hello, so basically I used to play my 3ds, until one day i accidently formatted it. When i formatted it i used my other 3ds that had some data. But now for some reason i want that data BACK. the way i formatted it was i changed the language for fun and then accidently hit format. My miis were gone, my streetpass mii plaza stuff were gone, everything was gone. The thing i care about the most was my mii. Idk why i am saying this, but the reason i want my mii is cuz i used it in my childhood, and i want to get it back. But the problem is that i created miis after i formatted it. I know it is weird to be desperate for a mii chararcter, but oh well. Please someone tell me a method to get data back on micro sd card, i really need it. the exact date i formatted it was march 29 2013. I know because it says i started playing on that date ,when really i got it on my birthday in 2011.
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wtf, i meant to put my data, but it auto corrected it but data

 

I don't know much about 3ds's, but have you tried to find an option to restore the data?