Cannot access Gov Gateway even after correcting surname on National Insurance number

I am looking for some advice. I have been trying to access my Gov Gateway account for a few months now. I had the incorrect surname on my National Insurance number when I first received it. I have amended it to the correct surname now and thought that I would be able to access my account. However, this is still not the case. I have called the National Insurance department and they have confirmed that the change of my surname has been done. I am at a loss as to what to do next as Gov Gateway will not register my correct surname as correct details. Once I try to put in the incorrect surname it leads me to the page in which I am asked to verify my identity. Of course I am unable to do this as my ID only contains my correct surname and not the wrong one that was initially placed on my National Insurance. I have made the relevant changes and made calls to confirm my details have been updated so I have no idea what to do next to gain access to Government Gateway. Any help would be much appreciated!

Hi,

If you have updated the name with HMRC this should be the version that is being checked for the verification. When you get the error message you will need to use the "get help with this page" link to report this.

Thank you.