Iphone 1st generation problem?

So basically I wanted to put music on my moms really old iPhone as an iPod, but it won't let me use anything that's not already on it. My mom isn't currently using the phone as a cellphone. The iternet doesn't work at all or any of the apps, I can only look through the photos and play the one song it has. I can't add anything to it. I just want to add a couple of songs

Return it

Are you trying to add them through iTunes? If the phone shows up as a device on iTunes, you should be able to add songs. Maybe the software needs an update.

I don't know if this will work but, plug the device in to a computer then open iTunes and click the music label in iTunes. Then drag the wanted items onto the device tab in the popup menu and wait for it to sync. This is what I always do for my iPod touch 4g and it always works, at least for me.