The sale started on Sunday at 9am, but I take your point, and have confirmed that my card has been charged with the game, as I posted later in this thread.
You get a payment reference number which can be taken in. If you check Event details on your E card, it's there (under Top up Ecash). Mine is done already.
As the ticket office is extremely busy, it is possible that cards will be charged on Wed or Thurs. I've been a gold member all season and not failed to have my card charged for three home cup matches.