GSCM Collection Department Sent me an "Urgent Notice: Debt Collection" for a debt I did not authorize carson City Nevada

Last summer I recieved a phone call from a so called rewards program which I originally thought was about my credit card rewards program. They offered a $100 VISA Debit Card free for trying some of their products on a trial basis which I was told I could opt out of in a certain amount of days. If I decided not to opt out then recurring fees would be charged to my credit card automatically according to them. I can't remember how many days were given for the opting out but it was all done on the phone and I was told the opting out information was included in the information package they would send me. Because of the confusion and there were supposidly different companies involved, when I tried to opt out, I just cancelled my charge card to avoid future payments. Now, 9 months later I get a "Urgent Notice: Debt Collection" demanding payment of $39.97 before 7/7/2014 of another $20 will be added to this debt. They offer 3 ways to pay it .. online at www.collectionpros.com., payment over the phone at 1-818-565-8870, or mail in the payment coupon included in the notice they mailed to my home.

The only way to dispute the debt is to notify them in writing within 30 days after receiving the notice and they will obtain and mail verification of the debt to me. Can't call them or contact them online.

When I originally called them back to cancel the orders they were supposidly all cancelled and no futher billing would take place. I thought that was the end of it until now over 9 months later.  

 The product was some generic pills called " Green Coffee Bean Max". They also include a site to send payment to at www.gscmcollections.com

I have perfect credit and this scam is trying to extort me into paying them to protect that. I have no idea if there is any other charges they might say I owe in the future as I was never sent any legit bills during the past months. Just this Urgent Notice