They don't want the stock. The stock is just the vehicle the use to scam people (and the "s****r list of people that bought this worthless stock, which demonstrates they will believe most anything). They want the upfront money that people will pay them believing, or hoping, for a bigger payoff in return. Once the money is paid, they will usually come back demanding more and more until the victim stops paying. The certificate will never leave the victim's hands.
The people being contacted are typically unsophisticated investors, mostly overseas. They probably have no idea the stock was revoked or what that means.
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