I'm not sure how well this applies but it could offer some ideas on out of nation dealings:
a few years ago I went on vacation with my parents to Cozumel, long story short my dad got convinced to buy into a time share. After paying like 2000 down payment and signing contracts my parents realized there was some bullshit in there that made whatever the deal was not nearly as spectacular as it was made out to be. Whatever it was, they wanted out, but we had to leave- vacation was over. After we got back to the states my mom started calling people. Lawyers based in the area of the business, the US consulate(or some form of US official living there), etc, and started basically getting as much information as she could, then communicating back to the business what steps she was taking in suing them basically.

After enough harassment/threats of suing they realized she was for real and didn't want to mess with it, they gave all the money back and did exactly what she wanted(probably would have danced for her if she asked).

Obviously this is a different type of case BUT it seems like a fantastic idea to talk to a US consulate in the Spain area and find out what your options are. Pokerstars will have to give information on the guys if the plan is suing them, which seems(with my very little knowledge of law) well within your rights.