Classic Collectibles Stamp investment - Ponzi scam North Las Vegas Nevada

I was contacted by a telemarketer about 3 years ago looking for investors in a error 1966 FDR stamp collection that was just released.  I was asked for a $1900 investment to secure the stamp for a 3 year period where i was promised a minimal average of 15% annual growth, and that I would need to hold on to the stamps for a least that 3 years to maximize my investment.  At which that point I would be recommended to buy into a 100 year old classic stamp of nearly $10,000 with a proven 12% annual growth.  I've recently researched more into this stamp and was able to come across geniune stamp sellers selling them for roughly $35.  (lessoned learned).  Once I discovered this I quickly try to contact them and the phone number was out of service.