Unable to get surname (outdated by more than 10 years) changed

I require a credit report to buy a property abroad. My surname on Experian reflects a surname that I had more than 10 years ago. I have sent numerous emails to them with all the required supporting documents and more to change my surname. They opened two cases which were closed without them making any changes. I then logged a dispute on my profile and attached the same information - they still haven't changed it. This morning I received an email from them that is an automated response (to an email I sent more than a week ago?) with a form of "thank you for contacting us. If you still need to log a dispute please fill in this form and attach the relevant documents". I have even tried their customer support email address to which I received a response to use the email address I have been using and when I responded that I have sent various emails to this address, they forwarded it to the same address and asked them to action it. Still no action...a month later and no feedback that they're processing my dispute or any updates to my information.