Oh, you needn't to be so angry. Maybe you don't know, but recovering deleted data on the phone is a simple thing today. I recommend a totally useful and professioanl tool to you for recovering deleted data. The deleted photos and videos must be found at once, so you should forgive your sister.
The tool is an excellent Samsung data recovery software, named Samsung Galaxy Recovery. It can easily recover deleted photos, videos, contacts, call logs, messages and other file types on Samsung, LG, HTC, Google and other Android brands' phone. Now, please follow the below guide to recover deleted photos videos from Galaxy Note 7 by using this Samsung recovery program.