Lloyd's Certified Philatelics Sold me Elvis error stamps for $2900 that appear to be worthless. Oceanside California

Lloyd's Certified Philatelics called me and sold me 2 sets of "Elvis error stamps" for $2900 that appear to be worthless. I recorded the phone call. The "investment" was supposed to be authentic and guaranteed. When I first called them back, I had to leave messages on a machine and never got a return phone call. Eventually their toll free number was disconnected. My research has led me to believe that I have been taken. I hope to find out otherwise. I have had other stamp companies confirm my stamps are real and marketable, but they just want me to buy from them before they would be willing to sell what I have. I found Lloyd's Certified Philatelics on Quatloos web site listed as a known scam company that has probably changed its name. They told me they had been in business for 30 years, and I believed them. I have the lady's name on the tape. My credit card company says I waited too long for them to be able to help me. I have been told by all of these stamp companies that I needed to waait until the stamps "matured" before selling them. They also told me these were part of a collection from Rosemary Clooney's estate. If in fact, I got screwed, I would like to know what I can do. I would at least like to get my $2900 back. Any advice?

Ken
winston-salem, North Carolina
U.S.A.