Customer cannot respond to a Newsgroup Response

Hello:

I am on the Microsoft US Complaint Management Team and we
have received an issue from a customer about being able
to respond to a Newsgroup Response. Supposedly, when the
customer gets a response there is an alias in the email
to which he can use to respond. When he uses the alias
it does not work so he cannot respond to a Newspgroup's
email.

Is there something the customer is doing wrong?

Thanks for the help.