Cannot transfer music from backup on my Toshiba laptop to my iPhone 6 Plus

I recently had to get a reconditioned iPhone 6 Plus due to dropping mine and shattering the screen. This was through Asurion insurance. I have set up the new iPhone and restored my data from a back-up of the old phone. It looks like everything transferred but my music. I have tried to sync the phone, drop and drag (it says that itunes cannot play this type of music even though it is in my iTunes Media file!) and use the transfer to iTunes in the file drop down menu. Nothing works. Help! Can anyone tell me what I need to do to get music back on my phone? I can't figure this out!