Want to delete all music on iPhone 4s.

Hello -

I just started using iTunes since I got my iPhone 4s. I've purchased one album, but only 6 out of the 31 songs downloaded, and all 31 songs are showing as duplicates. Those that do play don't play all the way to the end. I'd like to wipe all my music from my iPhone 4s to be able to start from scratch. However, I've had no luck by achieveing this through synching. I've even moved all my music from iTune and my Music folder to temporary folders, so that hopefully it wouldn't recognize. On the iPhone 4s General->Usage tab I've deleted Music, but it's stil showing up as taking 400MB of space, and the songs are under Music, though they do not play at all.

How can I delete all my music from my iPhone 4s and free up some space again?

Thanks!