Phone calls not coming through

Hi,

Is your phone maintaining signal - do the signal strength bars in the notification area stay on and how many bars are usually being shown? Do you have any trouble making calls from your phone? Do you know what the callers get when they try to call you and they don't get you and the phone has been on and not in use? Have you been told by them something like it was ringing why didn't you answer or I keep getting a recorded message when I ring you. The more information you can give the better we may be able to help you.