American Memorabilia Unprofessional sales practices Las Vegas, Nevada

In February I purchased at auction a Hank Greenberg signed baseball. The auction ad mentioned that the baseball had been certified by Richard Simon. The ad did not list the Richard Simon certificate. When I received the baseball I noticed that the Richard Simon certificate was nine years old. I contacted Richard Simon. He said that he had not done any business with American Memorabilia for several years. In addition, he acknowledged that his opinion may have been incorrect. On their website American Memorabilia lists JSA and PSA as authenticators for their items. They do not list Richard Simon. I sent the baseball to both JSA and to PSA. Both companies could not verify the Greenberg signature. I notified American Memorabilia. American Memorabilia said that "All sales are final. You accepted the Richard Simon authentication." I tried to explain to them "You failed to disclose that the authentication was outdated and conducted by third party that that you have not done business with for many years. Given that the company currently uses JSA and PSA, why wouldn't American Memorabilia get a current verification on the item?"  I asked for a refund. American Memorabilia refuses to take the ball back.