On October 9, 2018 I made a sale with the buyer an...

On October 9, 2018 I made a sale with the buyer and copper with market point, enter the ID number and I made him sign on my cell phone screen and send him the receipt by mail as it has to be done, time later comes against charge, and today the result of this chargeback was in favor of the buyer, and they took me $ 4570, and the merchandise had already taken the buyer, the operation was made, and the free market does not take responsibility for what happened, saying the decision they take the bank, free market has nothing to do and you do not know what the reason, by this means I want an answer ..