I only noticed that there is a problem when someone called me after I didn't reply to 3 messages he sent me. Turns out I never got them, and he never received the SMSs I sent him. Normally text messages get sent ok, but iMessages disappear. I tried to switch iMessage off, but the phone freezes complete when doing so, forcing me to hard reset (but at least iMessage was then switched off when rebooting). Normal text messages working fine. Anyone who's got a solution to this problem?