Surname Debacle

In December of 2020 I took up a savings policy with Momentum, upon completion of my application I was advised by my broker that Momentum is picking a different surname from that which I had used to apply with. I then notified him that I am divorced and therefore have reverted to my ****en surname. I then forwarded my divorce decree and any other documents proving such. Now imagine my surprise when the policy documents came back with the surname I had assumed when I was married. When I queried with Momentum, I was notified that it is the last surname they are picking up from their system. To say I was/still livid would be an understatement. This policy is not the first one I have taken post my divorce using my ****en surname and I have never had issues. Seeing that we can't get the surname issue sorted, even after supplying sufficient proof of my surname change. I would like my policy to be cancelled please.