I'm looking to purchase a ticket for a concert in Japan. The ticket is vended by Pia. For this particular concert, two payment options are offered: Seven-Eleven and Econtext. Both of these appear to require you to physically go to a kiosk in a konbini in Japan and pay for the ticket there. (Well, for Econtext, it says 「コンビニ・Pay-easy対応ATM、ネットバンキング、楽天Edyより各種お支払い方法をご選択いただけます」, but I imagine that transacting via Edy still requires you to be at a physical konbini.)
Since I am not located in Japan, this is something of a problem. I will, obviously, be in Japan around when the concert occurs, so I will have no problem picking up the ticket from a konbini when the time comes, but the payment deadline for the ticket is well before I will be in Japan (I'm preordering).
Is there any way I can pay for my ticket while being physically located outside Japan (specifically, in the US)? I know the language well enough to negotiate Japanese websites and communicate with Japanese people, if necessary.