Bag missing for more than a week

My 17 little sister came to Durban from OR Tambo for school holidays. She arrived 7 days ago. Her bag has been missing since she arrived. We have been calling daily. We have sent pictures of the smaller version of the bag. I am not sure how an entire bag disappears in an airport with little to no follow up. And we just want the bag and its contents back. Our mom passed away in August 2021 and my sister has stuff packed in that bag that my mom had gotten for her and that was my mom's stuff. Can someone please care about finding the bag. Deena has been helping, and he even asked that we call the head office because it seems like they are not taking his requests seriously either. We are really at our wits end :(