Have you formally asked them for a refund? If you do and they don't comply, you could try the route of disputing the charge with your credit card company. However, they do have the signed agreement which they will use to dispute the charge. That said, don't let that stop you from disputing the charge.
You will be hard pressed to find others with direct experience to answer your questions. Someone may do a Google search a year from now that turns up this thread and they then come in and comment. We often see old threads like these get dug up years after the last post due to this very reason. You might also do well to post in
r/scams on Reddit. However, many people won't come back after they have been scammed and are long past it. People who may have somehow successfully got their money back won't have reason to seek out these types of topics because all is good with their results.