Change email address of Amazon Seller Central account

Hello,
I have contacted Amazon Seller Support about 19087187186 times without any success so I’m wondering if anyone on here knows how to do it. I want to change the email address associated with my seller central account. I have been able to change it in many places, but there are a few places where I can’t find any way of changing it. Therefore, I still receive some occasional emails to the wrong/old address. The places I can’t change it are:

• Amazon Seller Central dashboard > Settings cog > Account Info > Identity information > Business and Contact Information… when i click ‘Expand >’ I can edit everything, except the email address which disappears.
• Amazon Seller Central dashboard > Three-horizontal line menu (top-left) > Reports > Tax Document Library > 'Your email address:***@***.co.uk. There is no edit option. I imagine it might be reading it from the above.
• Amazon Seller Central dashboard > Settings cog > User permissions > here I can see my old email address at the top with the (i) symbol next to it with ‘Manage Permissions’ and ‘Manage Global Permissions’ but no delete option. My new email address is on a second line with the same options but also a ‘Delete’ option.

I’ve tried changing my Login settings back to the old email address and logging in but that doesn’t seem to change anything. I tried doing ‘transfer account’ but again, I was able to change a lot of the company details but not the email address.

To confirm, if I go to Amazon Seller Central dashboard > Settings cog > Notification preferences, it correctly only shows my new email address in Notification Options and Contacts.

Anyone have any ideas?

Thanks in advance,
Adam