SSO Logins

We have some older user that use *********** to login to O365 all new users over the past two years have been configured as ***********. Recently configured SSO and users are configured with email addresses.  Could not figure out why some users were getting basic accounts even though they were set as licensed.  What is happening is when they login via sso it creates a new account using UPN instead of email address.  Is there a way to force zoom to look at the email address so that it can associate the accounts already in there?