They should not allow people to continuously use there app to scam people, and simply change their name from time to time, even though their contact information is completely the same. They allow no possibility of you to retrieve money sent, even if it was an accident. The only option is to ask someone to send it back.
Do not allow people to use their app, if they have complaints against them already. Allow a person to retrieve a payment that they sent by accident. All they have to do is give a person 5 minutes to stop payment. Have customer support for people who send money by accident, or who have been scammed, using their app. Considering the amount of transactions that they do everyday oh, there should be support. They have become a Haven for criminals.