LG mobile KM335 model
Invalid IMEI

Sir

i pinku singh purchased a mobile phone of LG mobile (model no KM335).

the IMEI no shown in my mobile is 135790246811220, but my n/w operator airtel says that it has a invalid IMEI no.my mobile dead from 1stdec. so why company LG selling an invalid IMEI mobile phone.what is the funda/strategy behind that. and how i resolve this problem for start my phone. we have origional bill/reciept of mobileshop from where i purchased mobile.plz help me

regards

pinku singh