Old mutual refused to pay death claim as they do not believe the unnatural death certificate, autopsy report and police statement.

Old mutual decided to reject my aunt's claim as a beneficiary to my late uncle's death claim who died from unnatural death as per death certificate and Autopsy report. Old mutual decided that they will not accept that unnatural death certificate in fact according to old mutual my uncle died from natural death(i would like to know which disease killed my uncle, you seem to know more than the pathologist doctor) and it was during waiting period (for natural death) thus the claim was rejected. How did they get to the fact of my uncle dying from natural death while his death certificate said unnatural still baffles me. This is beyond *********, actually i do not even understand how such a reputable company got to such a conclusion with no whatsoever evidence. Whats the use of submiting death certificate and Autopsy reports and police statements if you can decide from the top of your head that my uncle died from natural causes.