MTN Insurance- Shocking service

Would give zero stars if possible. My son lost his cellphone, I submitted claim with ALL accompanying documents and ref numbers on 18/10/2023. MTN Insurance only looked at it on 30/10/2023. After numerous calls and emails, I am told today that the claim is rejected due to negligence. the phone was lost and is covered by ALL RISKS, ie theft/loss/damage. What recourse do I have? I pay monthly for this and now cannot get another phone. Service is shocking, with a no care attitude!!