The Professional Couriers — I lost an item which is sent via courier

Address:

Professional courier coonoor

I have couriered few items from olavakkode, kerala to coonoor, tamil nadu.
Due to covid lockdown, everything was shut for more than 1 month so the item the recipient couldnt go and collect the item. After that i requested to return the courier back to me. When i recieved the parcel back, a titan watch worth ₹2700 with box was missing in it where all other items were there inside the parcel. When i contacted the courier offices in coonoor they not ready to provide me a solution on this. I called more than 15 times and they are telling they dont know about it you can go and complain. I don't understand why does the courier office open my parcel and take out one item from it since me or the recipient didnt receive or open the parcel. I request to take strict action on this and get my watch back.
Attached the order details.