I am so glad you came here first. There was a thread just recently about someone who fell for the scam and paid the money and got no puppy. It is really sad that they do this and they should be stopped!!!
I am not sure what you can do if you give out info. Some of the scammers will leave you alone once you say you are not intrested. On the other hand, others will call and harass you and give you a hard time. I don't really know what to tell you to do.
Oh and I am not sure if you know this, but I will tell you anyway. If you ever do decide to buy a puppy over the interenet, use
www.puppyescrow.com. It is used all over the U.S and many other countries. This way you know you won't get scammed and you will get a puppy and the puppy you agreed on. It is the best way to go and it is really safe and easy to use. If they live in the US then they have no excuse not to use this. Western union or money gram has no guarantee you will get a puppy but this guarantees you will. Just something to keep in mind if you ever do decide to buy a puppy over the internet!!!