whether it cost me $10,000 to do so, or $0.01, Zaizoun was to pay me 0.292 BTC to confirm it.
As a deal, Zaizoun should honour it by paying the agreed amount of 0.292 BTC. The deal was agreed by both of them at their own consent and they were fully aware of deal terms. Also nachius asked him twice. As for nachius being in DT it also isn't ethical to rip someone off by charging that high for which he himself paid low. I didn't expected such behaviour from a DT member.
IMO, the fair resolution would be for Zaizoun to pay nachius the amount required by btc.com to confirm the transaction.
That would be better.
