mostly one sends and leaves their ID in post 39578027

Hello help, I am doing that pay thing, sending funds and some sent to my account but I can't return it to them, because in the payment info the ids to return don't appear, what can I do? Because I search for their users and it doesn't appear either. basically something like this appears, an id but it is longer than the other id from their binance and with that one it doesn't let me.