Go to http://login.postini.com and entering your username and password. Please be sure you are entering @firststepinternet.com for your Postini username.
This will take you to your Postini Message center where you can modify your Postini Settings and see what messages the service has stopped. To check your Filter settings or add some one to your accepted senders list:
Click on the "Junk Email” settings link.
In the “Sender Lists” section, under the "Accepted Senders" category, type the address of someone you always want to receive mail from in the field provided. Click the “Save to list” button and that sender will not be blocked by the filter again. You can then log out.