TL:DR; Samsung pc to phone app was shit.
So samsung last time had an app that links music, etc from folder directly which means it doesnt copy but uses those files unlike itunes which was to navigate, but thats another thing altogether
I wanted to delete some music files from the app. I checked and checked and checked.. and I fucked up. I deleted the entire 4gb of music in my folder.
Everything gone. I tried recovering them after 1 hr, they were all corrupted.
I had back up but they were only 1gb of everything :(