itunes won't sync music to iphone 5

I've just upgraded to the iphone 5 32gb from 16gb and having a few issues with syncing music. My iphone 5 (16gb), I passed on to my mother as I wanted a 32gb, but I'm using the same apple id for both phones. I used restore from icloud to set up the phone initially. All my apps and books sync, but music will not sync no matter what I do. I've tried resetting the phone, it made no difference. I've tried erasing the phone and setting up from itunes, instead of icloud and it made no difference. The music appears in itunes as greyed out with a stationary cycle to the left of the music titles. I'm hoping someone can help me here or my only alternative is to take the phone back to the shop and get a replacement.