That's not good. Getting your money back depends on how you did it. If you paid by Western Union, MoneyGram, PayPal, or any other prepaid card you will not be able to. If it was through credit or debit card, contact your bank or card company IMMEDIATELY, or as soon as possible. They can probably reverse the charges along with getting you a new card. Be aware this caller is no way affiliated with Microsoft, but a con artist.