third party can;t hear me ,i hear everyone fine iPhone 4

dock speaker=swapped still peppole cant hear me ,camera and recoding works OK ,I CAN hear OTHER PPL

but they cant hear me

is it audio ic?

since it is on 4.3.3 with baseband 04.08.11 which has now been unlocked (it has also sam inside -but the unlock is official from at&t)it has also cracked screen ,may the screen effect it also with the proximity sensor ? (cause i think it shouldnt effect it ) ANYONE HELP ????