From Wowplus Announcement page;
Dear users,
we just found out, that Blizzard fixed a few of our hacks. For this reason, we'll not longer accept new subscriptions until we decided how to deal with this situation.
Regarding any refund question(s): Please be patient until we decided what to do.
We sincerely apologize for the inconvenience this may have caused. Thank you for your understanding and your patience.
Kind regards,
WuhTehFuh - Community Manager