Tracking iec code if not received or returned after dispatched

After filling for IEC code , which was send through postal delievery ,but somehow could not be received on time and neither could be collected from the post office.

It has been 15 days , above ,now if the IEC code courier had to be tracked ,how it can be done .

Also if a duplicate copy has to be obtained in the above case ,what is the process .

Please guide and suggest.