America's Elite Media Elite Media continues to charge after cancellation, had the audacity to send collection notice. Denver, Colorado

My wife and i had recently cancelled a magazine subscription, which i was opposed to getting initially. In order to cancel the magazine we had to pay a $400 cancellation fee, which we begrudgingly did.  The  cancellation took place 3/24/2011 and they subsequently charged us for four months without us realizing it. I changed my card though my bank so they no longer had my account information and they  are now sending collection letters. It takes a special kind of unscrupulous to charge someone after they paid a cancellation fee and then send a collection notice.  Is there any legal ramification they can actually take?  Or do i just sit through the collection letter junk and kiss my $200 in extra fees goodbye?