Stop the Phone Books

Today I sent email to the phone book company asking them to stop sending me phone books. I don't use the phone book any more and don't want the paper to go straight into the recycle bin. I was inspired by the site, 50 Ways to Help (link via Gist).

I was surprised to get this response:

"Our records have been updated. Thank you for using [name of phone book company here]."

Do you think they're serious? Or is this just the email they send when there's no procedure in place to deal with such a request? I guess I'll know in a year or so when I do or don't get any more phone books.