Just go to your bank, exchange the invoice total
in Yen, and then put the Yen banknotes into an
envelope (it's also recommendable to put the
money into dark colored paper first) and mail it
to the addressee via registered air mail.
No bank transfer needed, no post office needed,
no credit card needed.
It's a very simple way to pay the seller (I often
do it so as I have had similiar problems in the
Normally all sellers accepted cash payment if you
Hope this helps.