Air India — missing bag - searching from 7 months

Hi, i was travelling from fft to blr via mumbai via air india flight. During the travel i was checked out my check in bags at mumbai (International to domestic) and checked in again at mumbai airport. But i have not received by bag at blr. I have raised a complaint at blr airport but they are keep saying "tracing" or "mumbai airport is not responding" from past 7 months. I went to blr airport by personally many times but still i have not received any compensation nor proper update.

Pls find more details :

Flight no: ai 639 mumbai to blr
Complaint no : blrai46086
Status : no update
Raised on : 01 jly 2019

Thanks