Updating additions - How your tax free amount is calculated

I need to update the additions to my personal allowance but when I click on 'Update or remove' I get We’re sorry, but this page is restricted. Organisations cannot access this form, But I am not an organisation. Is this an IT bug? How do I do this? (Pease don t say I have to phone up!)

Hi,
You may have set up an organisational account when registering.
To allow us to confirm this, and advise you on how to rectify your account and tax code, you can contact us by webchat via Self Assessment: general enquiries- just click ' chat with HMRC online'.
Thank you.

So I've still not been able to resolve this - online chat said they couldn't help I had to ring 0300 200 3300 Rang 0300 200 3300, 1st agent said he was having problems with his desktop (!?!?) and would ring me back - he didn't Tried again next day, agent tried to tell me that you have now stopped allowing people to update your information online(!?!?). Asked to speak to his supervisor who decided to transfer me to the online helpdesk, after 15 mins waiting in a queue, got a message that they had been unable to verify my ID and cut me off! such joy!