Re: Help backing up Note7 before return....
Why not connect your current device to your computer, if you have one available? I make a folder (Joe's Note 7 for example) on my desktop and move everything I want to keep such as pictures, music, ringtones, notification tones, etc. The only thing I don't worry about are contacts as they are backed up with Google. Once you connect the device, give it a few seconds to be recognized and then you'll probably have to swipe down from the top of the device and pick "File Transfer". It usually defaults to "USB Charging".
Or you could always back up to the cloud. Also, one you have your new(er) device, Google usually gives you the option to restore from a previous device. Some have reported issues doing this (me included) so I set up as a new device to prevent anything.