X0XGabbyX0X
professional slacker
Hmm. Sadly I really do not know how to help in this situation. Usually when there is an issue with the update and hacked items, there is a specific error code. My best guess is that this is either a 3ds issue, a cartdrige issue, or an sd card issue. My best advice would be to contact Nintendo support. You can email or call them regarding New Leaf, but I would advise calling them since they will usually answer in around 10 minutes, while emailing can take weeks.
You can find the info here:
https://en-americas-support.nintendo.com/app/contact
You can find the info here:
https://en-americas-support.nintendo.com/app/contact