Get a police complaint along with your IMIE number of the phone stating you have lost it.
Then write to TRC with the relevant info. Along with that police report, NIC copy and your contact details. If you go to their office you will get a reference number then and there and TRC will do the needful. If they found the phone they will contact you.
TRCSL - General Contact
Telecommunications Regulatory Commission,
No. 276, Elvitigala Mawatha,
Colombo 08,
WP, Sri Lanka.
