I don't think you are in the wrong at all. I 
won't sell to people who flake out on me. If it 
was a true emergency then something could be 
worked out but as Lizzard so perfectly said 
(paraphrasing) -- if a person can't manage his or 
her finances or is not mature enough to keep his 
or her word, then you aren't obligated to that 
person at all. There's one thing to be nice to 
someone with extenuating circumstances but it's 
another to let them think this behavior is 
acceptable. It is not -- period. 

I would be horrified if I couldn't pay somebody 
and would never back out of a deal. Even when I 
might regret something I bought the previous 
night, I always go through with it. Most people 
(or at least most I've dealt with) are very able 
to do this too. 

The "testy" e-mail just goes to show this 
person's attempt either to assuage his or her own 
guilt OR this person is too self-absorbed to 
understand that choices have consequences on 
other people (for example, you might have needed 
that money for something important, etc.)

Wendy