I am dealing with these situations every day, so I know how you feel. Apart of being sad, it sucks all your energy.
Let me give you an example. AP divers are hot model, once I received a new batch I´ve fulfilled all the pre orders and left a couple of ones for inmediate delivery than obviously it was sold in a minute.
When it comes to payment sometimes it delays for 2 days or more. I never complain about that.
It was this fellow who told me he would make the payment next day. I waited for 3, reminded him, no answer, than I didn´t want to beg him to buy my watch so I sold it for somebody else. He came back after a week, I told him the watch was sold, than he made a 5 page email about how unreliable liar I am and how deeply dissapointed he is and he will report me on all forum boards about his negative experience.
I know that your guy, he waite for you for 21 hours only and I´m sure that it was a lost in translation miscommunication and the time frame of living on the different part of the planet.