Well, after looking at the thread, there seems to be a fuck up about the price and all. Maybe the seller ain't saying the whole truth. And maybe the buyer is right that the seller is trying to sell for 850M instead of 800M. And since it's bound, you can't just send the weapon back.
And if the buyer wants to pay the 800M but doesn't want to directly send the gold, because he's gonna have like 50M fee, he's waiting for the seller to actually send him a CoD with 800M.
Who knows who is right in this. If the buyer is trying to CoD for 850M instead of 800M, I would understand what the buyer means, as we see in the screens.
And if you send something without CoD, you can't just send it back. And it's bound, so you can't resend in another mail.