Heh, well as much as I favor the seller being 
the master of his auction, I would ordinarily 
say send it however the buyer wants and let them 
cry over their crushed and mangled cel as 
penance for being a tightwad.

However, this person seems to be very immature 
and irritating (plus I just hate hate HATE e-
mail shorthand) so I think I wouldn't want to 
accommodate them just on general principle.  As 
long as you stated what your shipping costs are 
in your auction they only have the right to 
politely ask that you send it another way - not 
demand. (And I've paid WAY more than $15 in cel 
shipping before ^_^)

And just what does "NOT a probleme ill still get 
the cel just like I did last time !" mean?  
Sounds ominous! You might want to see if some of 
Minion's chibi ninjas feel like moonlighting for 
a while!  ^_^