First of all, my computer crashed and i have to get it fixed, but i still have like 300 songs in my iphone, and i decided to hook it up to my other itunes in my laptop and i noticed it was also syncing the songs, so i unplugged it while it was syncing, my songs on my iphone are now unplayable. I have a iphone 4 3.1 F/W , Jailbroken

i was wondering is there a way i can recover them for free