I have mistakenly entered personal UTR number instead of limited company UTR number during account creation. How do I change this to the correct one?

I've tried emailing seller support many times but they never have a clue what I am talking about and either change the subject or refer me to another unrealated department just so they can press 'complete' at their end.

Also does anyone know what the effect this has on business/ taxes/ HMRC until I change it?

Thank you.