on 28-08-2017 13:16
on 28-08-2017 13:16
on 28-08-2017 13:18
Try first cleaning the sim card and rebooting the phone.
Have you recently changed sim?
on 28-08-2017 13:30
on 28-08-2017 13:30
on 29-08-2017 15:40
Do you have backup with the cloud? If you are paying for more than the free 5GB space apple provides you should have all your messages saved there, the ones that are lost, that is.