Cancelling phone contract overseas

It was sudden that I have to go back to my country for a few months and because I was too busy the days before, I decided to cancel my softbank contract at Narita airport on the day of my flight because I still needed to contact some people on my last day here in Japan.
But unfortunately on the day of my flight when I went to a softbank shop (or so I thought), they said they don't cancel contracts or cut phone lines. (Why???) The two shops on the 1st floor are closed (I went early because my flight is in the morning) while the one on the lower floor is the only one open. So now I'm Kinda worried because phone bills will pile up without me using the phone. Luckily I didn't use my credit card for the monthly bills, only a JP post bank account that's now empty. Anyone here had the same experience? I've been reading their website but I can't seem to find anything. Need info on who or where to call or contact (hopefully they have English support since my Japanese is zero)

if you fail to pay the fee, probably, your phone will be canceled and you can't get a new phone forever at Softbank, and for at least 5 years at other all companies in Japan.(because you are on their black list.)

from overseas : call +81-92-687-0025
http://www.softbank.jp/en/mobile/support/contact/

"IF" it is only for a few months. Why not just pay it. Cancelling a phone plan could cost more in get out fees than just paying for a few months.

A few to me is two or three.

You can also temporarily suspend your account so there are no monthly charges. Not sure if this can be done by phone however. Do you have any Japanese friends that can help you out?