What does the display icon mean?

Thanks for your response Rad2girls, But I don't think it's done for. the icon seems to come and go. I have realised that there is a pattern. It seems to come on when I have had a missed call, but not every time. I think only when it rang for so long that it was cut off. (I don't have voicemail). Then the exclamation mark goes away after a while (usually stays on the phone between a few days & a couple of weeks before disappearing). I still don't really know if that is the reason it comes up, or what it actually means, I'm just guessing. I still have no answer as I have not been able to find a manual that mentions anything about that icon. Majik :)

Werid..........mite be the fone is done for............like an ipod with the x for the eyes................