Old Mutual is just after our money, nothing else

My sister insured her husbands father with old mutual green light and started paying premiums in July 2019 and was told that there is no waiting period for payment should he pass away. In September he passed away and she submitted a claim which hasn't been paid out to date. She has been given the run around ever since she put in her claim. She was requested to send a medical report from the doctor which she sent in September but the payment has not been processed yet. Every time she makes follow ups they request the same medical report but they request that it be from a different doctor. She has been to 2 different doctors and has sent through the documents yet the payment has not yet been processed. The latest request from Old Mutual is that she must send a medical report from the hospital yet the hospital says that they cannot do a medical report for a deceased person. i do not understand why she is been given the run around because when she paid the premiums there were no issues. Old Mutual needs to honor their word as they had said there is no waiting period so can we just have our payment or they must give us back our premiums