I find the fact that you even stated this kind of unsettling. Not only do I find it as a way to belittle someone who is already being held up, but the fact that you have a "policy" online that says no gender is 100%, yet you still think of that kind of stuff, would kind of worry me, if I was the buyer; especially considering the boast of a 95% sexing/accuracy rate on your website.
So let me get this straight:
You are the one making up policies, yet they are so open ended that you could pretty much make them work any way you wanted to. And then say you bend over backwards for people? If you can send cookies to someone in Iraq and hold dragons for them for long periods of time, help out children at school, etc... why can't you just send back $300 and keep $50? He is being more than reasonable in this situation. Is it because he has "broken the trust"? Well guess what, he is STILL A CUSTOMER, a PAYING one at that.. Whether you are having trust issues with him or not should make no difference - you still have the dragon, and you have his money.
Instead of fueling this thread on, you could have already ended it and gave him back what he is wanting.