I can't get music off my iPhone.

My new 32 GB 4S is full because of 27 GB of music. I have selected "manually manage music and videos" on the summary page ( I get an error message that says "over capacity." Then under music I select one playlist with 7 GB of music and select "selected playlists..." When I click "Sync music" I get a warning that all other music will be removed from my phone. I hit ok. It says it synced. But at the end my phone is still full and music not on the playlist is still on my phone. What am I missing?? Thank you in advance. -C