Just stop replying to them, and don't give them any more personal information. Your address is public record, so they can't do much with that if you stop right now.
Just so you know, they don't usually ask for a credit card number, instead they ask for a bank account number "to deposit the winnings." Some people don't realize that they can also
withdraw money directly from your account with that number.
You may also wish to stop registering on public forums with your real name. Just a suggestion from one blonde to another.
