I don't recommend Braintree payments. They are not polite to speak with customer. They do not support new business. If you don't have "invoices proof " to send them don't waste your time contacting them. They will ask you all your personal and business information. Even if everything is legally correct I think that they choose you for your face in the picture at the end. They didn't give explanation of nothing. I just received an automatic email telling me that my application was declined. If all my information is correctly good. I cannot think another think than discrimination.
I cannot add proof of purchase because you don't purchase Braintree payments gateway. They just take a commission when your customers buy from you. As my application was discriminated i don't have any customer purchase..