Dial your mobile *#06# to know your IMEI number.
You are get your (IMEI) number. That will be 15 digits. This number is important in future. Keep it safe.
If your mobile stolen, the 15-digit number is likely to play an important role.
Mobile will be lost or stolen, you need to just login and make a complain here
If you do not know your IMEI Contact your Service Provider to get your IMEI
If you have any questions, do not hesitate to ask usSri Lanka Police