GSCM Collections Collect $39.97 for Unknown ,Discount Rewards. Several other complaints filed on same subject. Carson City Nevada

I received a letter from GSCM trying to collect $39.97 (Overdue) for unknown "Discount Rewards".  The Date of Notice was 02/05/2015 with a Payment Due Date of 03/07/2015, a "Collection Fee" of $20.00 to be charged if payment not received by 03/07.  I have no clue what this charge is for or who GSCM is trying to make the collection for.

I called the number on the letter (1-818-565-8870) and was greeted by a recording giving me the same information as is on the letter.  I called Directory Assistance for GSCM in Carson City, NV and the number given to me was 775-783-1790.  This number was not answered after ringing 15 times. 

When I pulled GSCM on line, there were several complaints from individuals receiving the exact same letter that I received.  I have no intention of paying but would like to know what the most appropriate course of action would be.  Any help is appreciated.