Windows 10: Trouble with bugged accounts in Windows 10 Mail app

I have two broken email accounts listed in the Mail app that I am trying to remove/repair. They do not display emails, and I cannot access the account settings dialogue to remove them like I can for other accounts. When I open Windows Settings>Accounts>Email & accounts, these two accounts aren't even listed, and when I try to re-add them I get an error code: 0x8004005.


Methods I have tried to remove the accounts include:

• Uninstalling the Mail app through Settings then reinstalling which removed all email accounts except the broken ones
• File scan and repair with SFC
• Uninstalling the Mail app through Powershell get-appxpackage *microsoft.windowscommunicationsapps* remove-appxpackage then reinstalling
• Taking ownership of the three microsoft.windowscommunicationsapps folders in "Program Files/WindowsApps" which fixed problems for some people somehow
• Uninstalling Mail, Running CCleaner and clearing Temp, then reinstalling

Any help would be appreciated.

:)