So basically how long does it take to get an item back that we sent COD that someone refuses to pay for?

Had four buyers for an item, but of course, naturally, since I am on Xbox, the chat system just dies and refuses to reply to anyone. So I stupidly send the item COD to the one buyer who wanted me to mail it. Big mistake, now my other deal fell through because some jackass decides that it's fun to take items hostage.