My name is ***** ***** I'd be happy to answer your questions today. I'm sorry to hear that this happened.
This is unfortunately a very common scam. The people who did this are usually located in Ghana or Nigeria, which means that US police can't just knock on their doors and arrest them. I hate to say it, but people who lose their money to these scam artists do not get it back. Even if you could find them, which is virtually impossible, a US judgment isn't worth the paper it's printed on in Africa, and most people can't spend tens of thousands of dollars in Africa to sue to get back a few hundred dollars.
The only thing you can really do is avoid this scam in the future. Do not send anyone money via Western Union or Moneygram to get something from someone you met online. Look for local puppy sellers so you can meet the animal, have it checked by a vet, and verify that it exists before you hand over any money.
The Internet Crime Complaint Center can investigate when you report the scam to them, I just don't want to give you false hope about the likelihood of getting the money back.
Also, watch out for follow-up scams. Sometimes in this situation, the scam artists will have a friend contact you and offer to get your money back - for a small, upfront fee, sent via Western Union. It's just a more despicable part of the original scam. Don't fall for it.
I apologize that this was probably not the Answer you were hoping to receive. However, it would be unfair to you and unprofessional of me were I to provide you with anything less than truthful and honest information. I hope you understand.