I have been in contact with a freelancer who is going to develop a private bot for me. He want upfront payment through PayPal with all of the bot features listed in the invoice for both partners safety. I mean if all features are listed in the Paypal invoice and he fails to complete the bot, shouldn't it be easy for me to win the Paypal case and get a refund? Or can he just say that he sent me the bot and I am lying and keep all the money easily? Is this the way to go for me as a buyer or should I force him to use a middle man?