I wouldn't do it.
Confirmed working, means it works....
but there is a backfire.
They give you time, but recall their money when you recall your account. Blizzard locks up your account and sends an email that says :
Please send 14.99 in a money order to {Blizzard Addy here}.
You cannot play until you do this, so you basically rape yourself. Don't do it. Blizzard gets mad when you get your money you spent on a timecard removed.
Chinese aren't completely stupid. They buy from blizzard store and put on there, you take back toon, they take back their paypal to blizzard store. Blizzard locks up the timecard, which rapes you..
Hope this helped.
Scrawl