As far as i'm concerned , I already got some fees 
for some cels I received before , depends on 
area , but for 650$ in france we need to pay 
around 250$ of fees , which is really a scandal !
anyway if you don't want such a thing anymore ask 
people to not put value of the cel on the parcel, 
and probably it will be ok , you can still ask to 
keep an assurance for the parcel but mention to 
not write down the price , already most of 
sellers do so , Asylum and most of Japanese cels 
shop .
So i hope next time it'll be ok for you
Take care 
G.A