What to do with songs that are not in the iPhone but iTunes says they're there?

Basically they had been converted from ORIGINAL CDs to mp3, if all the songs on the disc were "damaged" and impossible to load them in the iphone I'd understand, but there are albums that only have 2 or 3 songs out of 15. If I try to play them in my iTunes library they sound fine, as well if I play them on my iphone trough itunes, but when I look for them on the iphone, they're not there.
Any suggestions?

Hmm m

I have encountered a similar problem. Sometimes itunes is failed to keep pace with device. You may connect your phone and sync with itunes to have a try. And open the music or video app on the iphone to see if there are the files.