But service with claim

My father died and he had a policy with Momentum. We were instructed to complete a claim form which I did. We were three that claimed and two were paid out. Mine however was not paid. When I contacted them they told me that they cannot verify my bank. I sent them a letter from my bank as proof of bank, which they rep**** that they want three months bank statements(why DO THEY NEED MY BANK STATEMENTS IF IT WAS NOT REQUIRED BY THE OTHER CLAIMENTS AND WHY THREE MONTHS) The letter as proof of banking from my bank should be enough. After I sent them the documents I still have no feedback and i still await there payment in my account. There service is really a joke.Why the red tape with some people and the other paid smoothly.