Hi, i've had one of those old Philips c12 BT cellnet 'u' phones for a few years now and up until last week it was working fine. I use it to send text messages from arboad as it only costs 5p and I used it at easter from the Republic of Ireland and it worked fine. I make sure I make a call on it every so often to keep it active but last week I turned it on and IMSI Failed has came up on the screen. Whenever I call it, it says that the number is not recognised. Has anyone got any idea what could be wrong? I had about £8 credit on it. I'll be completely gutted if it's broke because it had one of the best tariffs ever.