Vistara Airlines — luggage misplaced by vistara

Address:	Gurgaon, Haryana, 122002
Website:	Vistara airlines

Unfortunately, I had taken a Vistara airlines flight from new delhi to Kolkata (07:30AM) on 06 september 2018 (UK747, ticket no-[protected]).I have checked in my luggage form Delhi airport, but could not find in Kolkata.I have logged a complaint to vistara executive at Kolkata airport on same date.They have given me 4 days time to trace out my luggage, but after 4 day they have given me time of 10 day, and in this period I have called them about 10 times and every time the have given me a new date to trace out the luggage. Now 13 days passed but I can not see any progress in this matter.It was a official trip and I had have to attend a project meet in Kolkata, but I could not attend it because all the necessary things was in this luggage bag.
I have suffered terribly, since I was not carrying any hand bag with me.
Please help.