Spice Jet Airlines — baggage missing - pnr p7c17s

Customer service Team,

Please find the attached itenary of my family's ticket who travelled last week. My brother's luggage wasn't received at Colombo Airport when they reached back on 13th SG01 flight to Colombo.
The response provided was very bad. It's now more than 3 days and we have received no response or compensation for such.
The airlines should have provided a compensation for the delay and should have intimated about the delay for us in advance. We have tried calling the given number in Colombo Airport and they asked to reach Spicejet.
My question is very simple. We travelled in Spicejet and you are completely responsible for our luggage. If it's missing, it's your fault. We need our luggage back As soon as possible. Also for the delay, i need a compensation given. We are facing difficulties since we have lost a luggage. I'm expecting an immediate response.

I have attached the invoice given at airport for missing baggage.

Person Name - GANGATHARAN KANISH ASHVINTH