PowerShell script to download from Web

Question

I am trying to log on web page using PowerShell and generate some. Although Powershell ISE gives some errors, current script works okay(sometimes log on sometimes not) but last part seem doesn't work to generate the Report by clicking the "CSV" Button.

Any help please?

$username = "username" 
$password = "password" 
$ie = New-Object -ComObject InternetExplorer.Application 
$ie.visible=$true
$ie.navigate("http://..../login") 
while($ie.ReadyState -ne 4) {start-sleep -m 300} 
$ie.document.IHTMLDocument3_getElementById('user_session_email').Value=$username 
$ie.document.IHTMLDocument3_getElementById('user_session_password').Value=$password
$ie.Document.IHTMLDocument3_getElementById('commit').Click()
$ie.navigate("http://..../activity_reports") 
while($ie.ReadyState -ne 4) {start-sleep -m 100} 
$currentDate= (Get-Date).ToString('dd-MM-yyyy')
$ie.document.IHTMLDocument3_getElementById('from_date').innertext= $currentDate
$ie.document.IHTMLDocument3_getElementById('to_date').Value=$currentDate
$Link=$ie.Document.IHTMLDocument3_getElementByType('submit') | where-object {$_.class -eq 'btn 
btn-default btn-sm'}
$Link.click()