Air India — missing of luggage

My husband has traveled from muscat to mumbai and had the connecting flight to calicut. From muscat he had a hand luggage but upon check in to flight ai 581
The authorities insisted to put his hand luggage as a luggage as they had no space in the aircraft cabin.
But to our disappointment he received only one of his baggage. He had traveled on aug 11 we have been to trying to reach the airport officers and had filed a compliant referral number :ccjai51472
We were informed that the bag was in mumbai and will be delivered to us in a couple of days but it has been a week now and there is no proper response from the authorities.
Lastly when we tried to call the mumbai office the office staff was very negligent and unresponsive.
Please respond to our issue at the earliest, hoping for a prompt response from air india.