When you delete a user from the Office 365 control panel they are moved into a recycle bin for 30 days so that they can be recovered easily if the deletion was not intended.
However, if you want to permanently remove a deleted user in Office 365 you can use PowerShell. For this task you will need the Azure Active Directory for PowerShell module installed on your computer.
First, connect to your Azure Active Directory by running Connect-MsolService and entering your admin credentials in the dialog box that appears.
To see a list of the deleted users run Get-MsolUser with the -ReturnDeletedUsers switch.
You can remove a specific deleted user with Remove-MsolUser and the -RemoveFromRecycleBin switch.
Remove-MsolUser -UserPrincipalName [email protected] -RemoveFromRecycleBin
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