There might be something fishy about it. Back then, too, frauds were prevalent. They are much more pronounced today, but they were there. You should ask Microsoft Support to help and guide you with that. Email address.
In 2011, bitcoin had little value and there were many faucets giving away bitcoins for free, so there is no scam in this case. The OP's problem was that he didn't withdraw it to his personal wallet at the time, so even if he could find the email and access the website, I can assure you that he will not get those bitcoins back. Just take a look at the current value of bitcoin, it's a huge amount, I'm sure that nobody would be willing to give you free money these days.