Indigo Airlines — Item stolen from checked in bag

Address: Mumbai City, Maharashtra, 400080

I boarded flight from Ahmedabad to Mumbai on 21/12/2016 via indigo airlines. When I landed Mumbai I saw one of my bag being opened and all the things on the belt and not in the bag. Also realised that one plastic box which was kept on the side of the bag is stolen which had pair of pins and some artificial earrings. The zip of the bag was open which had plastic box. When I approached the indigo counter in Mumbai airport the staff didn't help. She said their is no difference in weight. She checked the weight of my bag when I loaded in Ahmedabad and now in Mumbai. As the things that are lost in hardly any weight they are not taking any formal complaint. The matter over here is airline touching and opening your bags and not taking care of it when it was marked at fragile. My PANT number is K7R2GS and flight number is 6E 313. The staff who attended my query is Jayashree mumbai airport. Await your help.