Strange credit card charge

[Grumblebum]

This isn't really advice, so not sure if this is the best place for it, but anyway..

This month my wife noticed an odd charge on her Saison card monthly statement.
It said "ゼロ/１０円メール" for the company where the charge came from, and was for 840yen. My wife had no knowledge of this charge, as she has only ever used the card for shopping at the local department store.
Anyway, a bit of Googling came back with this:

http://www18.big.or.jp/~ggg/b/bbs/mbbs.cgi?mo=p&fo=kokuhatu&tn=0585

Seems that a lot of other people have had the same thing happen.
There is no question that the charge is incorrect, but what is surprising is that Saison won't block it - they say the charge will go through anyway(the card is paid by direct debit) while they "investigate" it. And we *might* get it refunded depending on the outcome.
This bothered me because with my (admittedly overseas) Mastercard, if I dispute a charge, they will block it pending investigation.

Anyway, from what I've read at the above site, the source of these Zero charges looks pretty suspicious.
What worries me is that my wife is adamant that she's never used her card in any way which could have resulted in this company having her info - she's never used it for Internet or phone shopping, only ever in stores (and mostly large department stores). We're getting the card cancelled, anyway.

It just occurred to me that I probably should have asked a question here - has anyone else here got experience with disputing charges on Japanese credit cards?

[homesweethome]

This is not directly CC charge related but we had an account with the Nokyo (Agricultural Cooperative) in which they were directly withdrawing payments for gas (LP) kids school lunches, nursery school fees, etc. Then we noticed they were "deducting" amounts each month for various things they would call "service charges" "interest" "Late payment fees" (even though we never made a late payment), they just seemed to be tacking on any label as an excuse to withdraw funds. It came to be more than just a few yen a month, actually increased to several thousand yen a month before we noticed. We are not the only people this has happened to. We cancelled all our accounts with the Nokyo and complained to the tax office. They tell us we are entitled to a rebate of the amounts illegally withdrawn plus Interest!, but they don't say how much this "interest" might be. We filed for a "return of funds" with the tax office but have not heard anything for several months. They are supposedly doing an "investigation" into the Nokyo, but I am not holding my breath. FWIW