Office 365: Get count of messages sent for user

Connect-ExchangeOnline

$SenderEmails = @("user1@acmecorp.com")

$StartDate = (Get-Date).AddDays(-10).Date
$EndDate = Get-Date

$finalReport = foreach ($Email in $SenderEmails) {
    $userTraces = Get-MessageTraceV2 -SenderAddress $Email -StartDate $StartDate -EndDate $EndDate -ResultSize 5000

    $uniqueEmails = $userTraces | Group-Object MessageId | ForEach-Object {
        $firstEntry = $_.Group[0]
        [PSCustomObject]@{
            SenderAddress = $firstEntry.SenderAddress
            # Keep as [datetime] object for proper sorting
            Date          = $firstEntry.Received.Date 
        }
    }

    $uniqueEmails | Group-Object Date | ForEach-Object {
        [PSCustomObject]@{
            SenderAddress = $Email
            Date          = [datetime]$_.Name
            SentCount     = $_.Count
        }
    }
}

$finalReport | Sort-Object Date, SenderAddress | Out-GridView