missing baggage

My daughter "Nikhita Saluja" age 13 years was travelling on an e-ticket from Delhi to Patna flight no-IC 407 seat no.-16D on 14/05/2009 thursday . After checking in the airport she handed over the luggage to the authorities for x-ray and other formalities. Later she boarded the flight with her boarding pass and hand bag leaving the suitcase to be loaded in the flight. but after reaching Patna Aiport she found that her suitcase was missing. On enquiring from the authorities at Patna it was told that mistakingly the suitcase might have been left at the Delhi airport. we were told that Arrangements would be made to get the missing suitcase on the next day's flight . we have been enquiring constantly for the missing suitcase from the authorities and were told that the suitcase has been found and the same would be delivered at patna airport vide consignment n0.- 022264 but two hours utter dismay that till date the same has not been delivered.
We are therefore claiming the damages which amount to approximately Rs.18000/- .If the same is not paid within a fortnight's period, we shall be compelled to file a suit against you for which you shall be held responsible.
Incase the same is restored, please be kind enough to inform me at 9810000136 or on my e-mail address.