Frustration with updating name change

I have been trying to change my surname since 6 April 2023. Each time I follow-up I’m told that it will take 2-3 working days to update. I provided all the necessary paperwork in April but I’m still waiting for the issue to be resolved. Two days ago, at around 9 am, I spoke to a consultant who said it would now take 2 hours to update as she had escalated the issue. She promised that she would send me a membership certificate to prove that the change had been made. I’m still waiting.