Cannot get a problem resolved after 4 moths of phone calls and emails

I have had an account with this platform for years and was generally satisfied with the service and web access. Around August 2025 I attempted to draw a statement of my account on the web portal as I had done many times before, I was met with an error message saying the there was a failure to "Failed to load Investor transactions", with a message about the nature of the coding problem which was obviously related to the apostrophe in my surname. Since August, I have contacted them repeatedly always with the same reply that "It works on our side". Today I phoned and asked if there was somebody that I could speak to resolve the problem. I was told to send another email and when I explained that the previous emails had not helped and the latest email had not got any response, I was cut off. Is there any way to resolve a relatively simple problem with this business?