you need to have the mod that was taking care of the dispute do that.
Alright I gave in and I sent him the extra card thanks for responding'
if you send in a PWE and it gets damaged, it's your responsibility to take care of it. at minimum, you should replace the card. you could ask if he's willing to send it back and not send to you and just cancel the trade. that does set him back the shipping cost, so you may want to offer to pay for that.
the trading rules of the site cover sending cards in PWE's and it is highly suggested not to use them because this stuff happens.
I am making a trade with aurorasdad and I was a noob trader at that time so I sent it in a white envelope (not knowing it would probably get damaged). It was a 15$ card BV wise and I was getting about 6 or 7 cards that were worth about 10$. The card got damaged so now he wants me to send him another card worth 4$. I find that completly unfair. Now he won't even send me back the card I first mailed to him. I would like my card or my side of the deal please. He is also talking to a mod about this. I know that in the future I should send with bubble envelope. Also everyone else I traded knew I was new to the site and said next time make it bubble but this guy won't even give me a chance