Sorry to hear that you fell victim to a phishing scam. As stated above, there's never such thing as free points, so keep that in mind next time a friend tells you about such an offer.
Unfortunately no one here will be able to help you with the problem, just call Microsoft help back again and explain the situation. If they can't resolve it, delete the account and make a new one. But definitely do not add your dad's credit card back on to the account until you get this straightened out.