Know your EMEI number
Every mobile phone has a unique 15-digit electronic serial number known as the International Mobile Equipment Identity (IMEI) number.
You can check your IMEI number by dialling *#06#. This should make the serial number pop up. This number is unique to your handset, so write it down and keep it in a safe place in case your phone is lost or stolen.
If your phone is lost or stolen you should then provide this number to your mobile phone service provider so that no more calls can be made from that phone.