Ok - so you did an exchange and a random player that you didn’t think you out in the exchange is missing?
did you by chance autofill the exchange?
Did you check that there were not extra rows below the visible top row that perhaps had been autofilled as well?
in any event - contact customer service via the in game settings menu and tell them you have missing content (not a bug - missing content) and they can check what happened, and whether it is recoverable (if you used it in an exchange though, probably not)