What should I do if I lose my mobile or somebody have stolen it?

If one day you don't found your mobile don't get crazy and keep calm. You can call with other phone to your  mobile and wait for listen the melody of your ringtone and there is your phone.

But if somebody had stolen it, found your mobile is more dificult. You should call at your company and ask if they can block your SIM card. Later report the theft to the police and ask if they can block IMEI code of your phone.