First please register a police complain with all the details.
Then log on with your Nokia or Windows account on the web, it will help you to find your phone.
If this isn't due to your phone being dropped in water, try doing a soft rest. To do this........Hold the "down volume" and "power button" at the same time for ten secs, until it vibrates, then let go of those buttons. The phone will now reboot. This will not erase any of the content on your phone (i.e., games, contacts list, programs, etc.)Hope this helps. :)
That could be the result of someone trying to jail break the phone.
The IMEI numer is a specific identification number for that specific phone and if changed will render the phone useless.
Question edited for clarity.
So the phone was likely stolen in Australia and shipped to Sri Lanka for sale. For the technician to unlock it by playing with the IMEI, it must have been PUK Locked AKA a SIM Lock. To remove a normal customer set PIN Lock, you just do a hard reset which scrubs the phone clean and reloads the operating system with no lock.
A PUK Lock can only be removed by the carrier that provided the phone. The technician tried the impossible task of removing an RSA 128 bit encryption lock by playing with the firmware and corrupted it.
You have three choices
1. Give it back to the technician and tell him to fix his mistake
2. Send it to Nokia to have the firmware and IMEI reinstalled
3. Throw it away.
Have a read of this Fixya Tip I wrote.
https://www.fixya.com/support/r26230986-phone_asks_puk_code_ask_another_way
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It is normally recommended you Don't post your IMEI on websites. It is a security code for that phone.
Usually the IMEI number has to be reset by your network provider. It normally cannot be done directly from the handset. Did the handset accept the new sim card. Some handsets can be locked to a specific network and changing network can stop your phone from working.
