With any unsolicited bulk email (spam) the sender is legally bound to give you the option of unsubscribing from future emails. But this site will have sold your details on to many of them I have no doubt.
In practice whether this will work is another matter. Fortunately, being in the business, I have my own email server and anti-spam appliance. That won't help you though.
Extortion through technology is a whole industry now. I absolutely deplore it and have seen so many people caught by it. I would even go as far as saying it upsets be more than brake lights in traffic queues!