Dead end requesting information

How difficult can it be. I have requested a paid-up letter since the 07th of April 2025. I have visited the branch where I required a statement and requested a letter. The lady was rude and didn't want to assist me. I phoned; I have sent many emails. Today I phoned again, and the lady said I need to visit the branch...really.. I bet when I get there, they will not be able to help me!!! Worse service ever!! It is a dead-end requesting the letter...I complaint on Hello Peter and I only got a mail said they are investigating the issue...again...dead end.. What should I do to just get the letter?????