MCDutchGamer

i appeal the first time but it got denied

Personally I dunno if you were actually hacking or not, if you still believe you weren't hacking after this appeal, then follow the instructions above posted by other members.

This time it's on youtube, that video is proof enough.
i hope i will get unbanned this time

You can apeal here: https://appeals.cubecraft.net/

Appeal*

You were banned by Sentinel for using a illegal client (https://appeals.cubecraft.net/find_appeals/MCDutchGamer), so there is a reason. You can appeal over here - https://appeals.cubecraft.net/