His knife never arrived, therefore he did NOT hold up his end of the trade agreement. This has little to do with "being satisfied;" the terms of the deal were simply never met by the other party. You are absolutely entitled to a trade back. You could trade back if his items were not described accurately, so not being there at all,is OF COURSE grounds for a transaction reversal. This guy should have shipped the first package insured, and if that's where the knife was originally lost, then he'd have to work it out with the shipping agency--not you. If he doesn't rectify this discrepancy, I whole-heartedly agree that a ban is in order, lest he try this nonsense with some one else.