Refusing to pay-out

Cruelty!Cruelty!...My sister just lost her partner of 14 years .She submitted all the documents needed last week.After not getting a notification from the bank.She went to one of the old mutual branches.And she was told there was a missing document.And that document is a letter from her partner family stating that yes"she was living with her partner for the past 14yrs".I have never heard of such.I have gone through your reqiurements on claiming for a funeral cover.No where it says such.The funeral is on saturday no arrangements have been done.My sister is unemployed and the only money we thought we will use is that from Old mutual.The pain of losing someone is unbearable,But I feel you are adding to this trauma.I have a life cover with you guys but now Iam panicking of what will happen to my children when I die?