Registering as self employed HELP

I am going around in circles trying to register as self employed - the government gateway won't recognise my identity - I suspect this is because all my ID is in my married name, and I stupidly didn't realise I needed to make the government aware of this when I got married 11 years ago and was in a PAYE job. How on earth do I get past this to be able to register as SE?

Hi LauraAstley,

If you are unable to register online please see the section 'if you cannot register using the online service' or contact our Self Assessment department by webchat
Register for Self Assessment

Thank you.

I've been trying to access the webchat for a month now, no one is ever online to help. I've used all my ID to try and identify myself, I cannot get into my account at all. I am at a loss as to what I am meant to do. There is no phone number, no email address and no answer from anyone.