After 2 years last night my phone suddenly said the SIM Card is not a Verizon card and would not let me call Voice Mail using the icon or make phone calls lin general (said network not available), though I could access the internet. This morning when it was still doing it I turned it off entirely, waited a couple of minutes ,turned it back on and it appears to be working (that didn't work last night), but I need to know why it did it because this phone is crucial to my business and I need to know if it needs to be repaired to prevent this happening at a crucial time.