Ask How do freelance platforms handle cases where a client claims the work was already done by someone else?

[Edward22]

This sounds like an unusual situation, but it does happen. A client receives your completed work, then comes back saying someone else had already done the same job before you. It puts the freelancer in a very uncomfortable position, especially when payment is still pending. I do not know if platforms have a clear process for investigating claims like this or if they just take the client's word for it. What happens in practice when something like this comes up?