Town deleted in ACNL, what can I do?

I recently found the old Animal Crossing New Leaf Nintendo card from my brother. He does not play the game anymore and so the city was mine now. He never really had time to play, so his city was a bit empty, with 6. Million Sternis in his account. Tonight (just 10 minutes ago) I wanted to sell his city to Tom Nook. But I came with Melinda on the wrong button and thus ONLY the city was deleted, NOT sold! I cried because you always get so much money. I then (stupid) turned off only after saving the 3DS. Does anyone have a hint?

I'm sorry, but what was deleted once deleted.

Only on a PC could you restore a part or everything with a program, but on a console something like that does not work (except in an illegal way, but I do not know it).