Fraud HELP!!!?

OK so my gf found this dog in Decatur, GA for $400, the seller (Natasha Miles) said that she would take 300 for it since it was going to be a present for someone. To make a long story short, my gf paid the $300 then natasha said that we would have to pay a $150 for insurance to put the dog on the plane in case of emergency. We sent that and then she said that she would change the flight to a later time. She had all of the information that we needed but every since i sent that last payment , she hasn't emailed me back. Is there any way we can get our money back after she's already received the payment?? HELP!!!!