How to get songs off an iphone 4s?

I just got my dad's old iPhone 4s and don't want his music. Whenever I try to hook the phone up to my computer and delete them through iTunes it doesn't work. What do I do? I don't want to restore it to factory settings because I've downloaded apps and have all of my contacts on in.

Usually (if the iOS is updated) you can slide right to left on a song and delete it from the phone.

Try again on iTunes make sure it's up to date if it doesn't work take it to the apple store make a Appointment on the apple store website and tell the Genius to take of all the songs tell him that you couldn't do it yourself. None of your Personal information will be Deleted.