I believe the purchased one will come with a certificate for your free selections. Or, when they have your payment for the regular priced one, you should be able to place your order through your account online.
They will send you the featured title every month if you do not respond. Of course you can send it back unopened at no cost. I have my account set up so that I do not have to respond, and they won't send it. I did that so long ago that I don't recall how to do it, unfortunately. Try customer service.