Metropolitan enquiry that staff can give a clear response to

I would like assistance with an old policy for my late Uncle. My grandmother has in her position the funeral cover application form which has her name put in as beneficiary however the policy was allegedly paid out to my Uncle's then girlfriend. My grandmother has never gotten a satisfactory response from your staff as to how that happened. I would just like assistance with proof of some form that either the funeral policy was never paid out and it was just a rumor that it was paid out to his girlfriend or maybe that he had changed the beneficiary to the policy without my grandmother's knowledge. Please assist. She desperately needs closure on this matter.