i dont think they will take your mobile, they might thinks its a bomb
you should be able to get your texts from your old phone, back them up to your sim, transfer to your pc with a app, by usb cable or blue tooth etc
only thing you might get back are any orginals docs you send and anything they don't need. so any orginals make 2 copies of, one for the embassy and one for you, in case you never see them again
