puppy scam

So I found a chihuahua breeder online from the States. I found a puppy on her website that I wanted so I contacted her by phone and she made arrangements to have the puppy shipped to me in Canada. She told me that she would send me other pictures so I could see the colour of the puppy's coat better. This took a week, and she finally emailed me pictures the night before the puppy was to be shipped. The "puppy" was double the size and pretty much full grown. I told her that I did not want her since it was not what I purchased. I was supposed to be purchasing a puppy. She did not ship the dog to me, but she is now refusing to refund me the $500.00 that she charged to my credit card. I wanted to know what my rights are and if I have a chance of getting my money back. I also heard that you can dispute certain charges with Visa and they will take them off. Is that possible? Thank you, S.G