Script to remove secondary alias from all mailboxes

Hey Team, 

I need to use a script to remove @domainname.com from about 120 mailboxes. The environment has several different domains added to the default email address policy. This is for exchange 2013. 

http://stevehardie.com/2012/03/exchange-powershell-remove-address-from-list/

I tried using the above script in my test environment but it does not work. Any ideas? I thought this would be pretty simple, but it sure doesn't look that way. 

Thanks, 

Robert 

Robert