Unable to log in following change of email address

I followed the process to change the email address on my basic account and received the email to confirm the change. Unfortunately there was no prompt to remove the 2 factor authentication first, and I can no longer login. The authenticator app is connected to my old email address so it doesn't recognise the codes. 

I don't have recovery codes.

I can't do a password reset as it wants a code.

I can't contact support directly as it's a basic account.

I can't upgrade the account as I can't login.

Chatbot is useless.

How can I get it reset?