This question is about one other client. She sells event tickets and here is the scenario that she has faced a few times.
1] She sells seat ticket X to a person A (this is a normal thermal printer event ticket)
2] Person A claims that he never received the ticket and asks for a refund two days prior to the event.
3] Client refunds the money, asks the client to return the tickets in a prepaid envelope that she send to client and meanwhile sells a new ticket to seat X to a person B
4] both A and B show up at the event with their respective tickets.
There are some variations to this scenario. Sometimes B gifts the tickets to C, or A resells ticket to D or A asks for a refund after the game is over and so on.
How does one deal with this kind of fraud? The client has about 15% commission. So if there is a fraud, profit from 7 tickets is wiped out.