I was involved in an accident and I am insured with them they send someone to come and tow my car, I am very sure that my car had a brand new spare wheel which I never used ever

I was involved in an accident and I am insured with them they send someone to come and tow my car, I am very sure that my car had a brand new spare wheel which I never used ever. But after they repaired the car the spare wheel is nowhere to be found. Since last week they said they will investigate my lost spare wheel within 24 hours. They promised will get my feedback, even today I never heard from them nor update me with what is happening. They don't even bother to contact me and my new spare wheel was lost in their process of repairing my car.