So was able to get them to send me the form for compensation after 2 months. The local office in Kolkata did not help much but did give details of seniors in Bengaluru which pushed them to at least send me the form.
Would anyone have a reference point on what to expect from them as compensation. They are asking for a list of items which I am providing as much as I remember and value which is very difficult to ascetrain. The total weight of the bag is 10 kgs and lost sector is LHR-BLR-CCU (bag lost in BLR).