Microsoft Teams connecting with wrong tenant on iphone

We have an old Microsoft account we used for licensing MS Office for a couple users. We no longer use that account and now have a new company wide account. I've had a number of login issues with one of the users on this old account where various apps keep trying to use the old account and not his new one. The e-mail address is the same on both so that is what is causing the conflict. I've been able to work through almost all of the apps on his computer and iPhone, except for MS Teams. For some reason Teams keeps trying to connect using his e-mail address for the other account. We have uninstalled and reinstalled the app. We've done the delete procedure to delete the app and all it's cached data and re-install. I've checked his password manager on the phone and none of the accounts show there. And I went into his account settings and removed any Microsoft accounts I could find there. Teams still insists on using the old account. I get this error when trying to log into Teams on his iPhone:

AADSTS50020

after the error it has a request ID, Correlation ID, Timestamp, and Message. In the message it shows the login account, the identity provider https site, then it says "does not exist in tenant 'ourcompany, Inc' and cannot access the application."

That is how I know it is using the wrong account...the old account was set up as ourcompany, Inc while the new account is just ourcompany. Anyone have any idea on how to get this old account out of the phone without doing a factory reset?