Granular permission for shared mailbox

Hi guys,

I'm trying to apply granular permissions to one of our shared mailbox, but my setup not working. The purpose is to disable email deletion for specific user, however TEST user still able to delete any email from shared mailbox (tested on OWA)

I've used that article: http://msftexchange.org/granular-outlook-permissions/

So, what has been done:

PS C:\Users\Administrator> Add-MailboxFolderPermission "support@domain.com:\" -User TEST -AccessRights FolderVisible

FolderName           User                 AccessRights
----------           ----                 ------------
Top of Informatio... TEST           {FolderVisible}


PS C:\Users\Administrator> Get-MailboxFolderPermission -Identity "support@domain.com:\Unsorted recovered"

FolderName           User                 AccessRights
----------           ----                 ------------
Unsorted recovered   Default              {Reviewer}
Unsorted recovered   Anonymous            {None}
Unsorted recovered   Me        {Owner}
Unsorted recovered   TEST           {Reviewer}


PS C:\Users\Administrator> Get-MailboxFolderPermission -Identity "support@domain.com:\"

FolderName           User                 AccessRights
----------           ----                 ------------
Top of Informatio... Default              {None}
Top of Informatio... Anonymous            {None}
Top of Informatio... TEST           {FolderVisible}

Hope you can advise me the solution.