Syncing mp3s to jailbroken iphone (problem)

[KillaSkrilla]

Hey i got a huge problem, spent weeks putting music on my iphone, making the perfect library. And everything worked fine, until i decided to add a couple of albums today and all of a sudden everything dissapeared. I tried syncing it again. And at first it seems to work. The 20GB of audio is showing, but then it dissappears again.

Sorry if im bad at explaining but im sure im not the only one with this problem. This is really frustating spent alot of time putting music into the phone, was gonna give it away as a birthday present tomorrow but seem like i wont be able too. So if anybody can give me any insight on how to get my music back on the phone. Please do...