First Flight Couriers — missing items from box

Address:

Pune, Maharashtra, 411028

On 20th dec 2018, i booked some clothes of mine and my husband's from pune's hadapsar branch of first flight courier. It has to be delivered to lucknow location. When we received the box, it was well in condition and everything seems alright from outside, so we didn't opened immediately. But when after 2-3 daya we opened it, it was found that one packet of clothes which had two sarees, was missing from the box.
We went to courier centre from where we booked it. No good response was received. They were saying they cannot say, as they sent it as it is. Called to customer care representatives for pune location, they were rude too. I don't know what to do now as no one is responding correctly.
My assignment number - m991a0140727