Thing.ps1

[CmdletBinding()]
param(
    [Parameter(Position = 0)]
    [ValidateNotNull()]
    [PSCredential]
    $Credential = [System.Management.Automation.PSCredential]::Empty,

    [Parameter(Position = 1)]
    [ValidateNotNull()]
    [uri]
    $ConnectionUri = 'https://outlook.office365.com/powershell-liveid/'
)
$SessionInformation = @{
    ConfigurationName = 'Microsoft.Exchange'
    ConnectionUri     = $ConnectionUri
    Credential        = $Credential
    Authentication    = 'Basic' 
    AllowRedirection  = $true
}
$Session = New-PSSession @SessionInformation
Import-PSSession $Session
 
$RecordList = Get-Mailbox -ResultSize Unlimited | 
    Where-Object EmailAddresses -like 'smtp:*hiddenforsecurityofclient.com' | 
    Select-Object -Property DisplayName, @{
        Name       = "EmailAddresses"
        Expression = {
            $_.EmailAddresses | 
                Where-Object {$_ -like "smtp:*hiddenforsecurityofclient.com"}
        }
    }
 
foreach ($Record in $RecordList) {
    Write-Verbose "Removing Alias $($Record.EmailAddresses) for $($Record.DisplayName)"
    Set-Mailbox $Record.DisplayName -EmailAddresses @{
        Remove = $Record.EmailAddresses
    }
}
 
$RecordList = Get-Mailbox -ResultSize Unlimited | 
    Where-Object EmailAddresses -like "smtp:*hiddenforsecurityofclient.com" | 
    Select-Object DisplayName, @{
        Name       = "EmailAddresses"
        Expression = {
            $_.EmailAddresses |
                Where-Object {$_ -like "smtp:*hiddenforsecurityofclient.com"}
        }
    }
 
foreach ($Record in $RecordList) {
    Write-Verbose "Removing Alias $($Record.EmailAddresses) for $($Record.DisplayName)"
    Set-Mailbox $Record.DisplayName -EmailAddresses @{
        Remove = $Record.EmailAddresses
    }
}