Hi
Unfortunately you have removed the AD/Exchange details before disabling the account in EV. The way round this is to delete the users reference from the Enterprisevualtdirectory db > exchangemailboxentry table.
This example sql query will allow you to find if the user is still in EV or not.
use enterprisevaultdirectory
select *
from exchangemailboxentry
where mbxalias = 'mike.smith'
If this finds the user you want to remove you would then
use enterprisevaultdirectory
delete from exchangemailboxentry
where mbxalias = 'mike.smith'
You do this at your own risk, I would advise making a backup of you evdirectorydatabase before trying this.
This will clear the user, you can then delete the users archive if you wish. One word of warning if you decide at a later date that you wish to "undelete" the users archive then you would need to restore your complete EV environment, there is no brick level restore for EV. What you might want to think about is exporting there archive to PST and then deleting the archive. The PST can be ingested at a later date if you wish.
