dude
I'd stop what you're doing right now if I were you as you don't understand what you're doing.
Spread bets have nothing to do with InterActive brokers and till you understand points such as this your are on course to lose all your money, that you can be 100% assured about that.
Go back to your books and market websites and get studying, the markets are no place to learn real time.
And as for the other message about "Professional Diligence Foreign Exchange Inc" I'd steer well clear of them unless you 100% want your money to disappear. Plus, the person who wrote the message either hasn't a clue what they're talking about or they're a scammer. Short selling is NOT banned.