The guy really has no obligation to reply to you Ivan Millet, and to look on a lack of response as inferring guilt is circular logic, and such reasoning should be confined to people who work for holy inquisitions and the like.

As for the ticket information, now that is a bit suspicious I agree. I have not heard of schools buying tickets for teachers upfront for a long long time. There was what was considered a golden time for foreign teachers here in China, when you had a lot more perks, the market was not so saturated, and schools "had" to provide said perks to get you to come here. That isn't the case anymore, and hasn't been for a long time. If this guy actually demanded a ticket up front, something he almost certainly must have done since no schools simply "offer" this anymore, then indeed that could be seen as unreasonable in today's current ESL market.

All of that being said, I don't know enough about the back story to comment in any specific way. I'll only say that a deal is a deal, and once you make it, you should stick to it, unless there is some unforseen circumstance of an extreme nature. Telling the guy "You're old" hardly seems to fall into that category, I mean heck, they knew his age since day one. It's very likely they found someone locally and saw a chance to save some coin, and we all know how good schools are at paying airfare at the end of a contract in China.