This is the final straw for me with Accor. When something does go wrong the support for Platinum members of Le Club is non-existent. The staff are defensive and talk over you and uninterested in resolving problems. I attempted a series of bookings for Heathrow (Novotel & Sofitel) which returned a variety of error messages - mainly the card issues mentioned by others in this thread. When I called in to Le Club they could not even tell me whether the reservations would be cancelled or not.
After a past experience where they lied to me about stay qualification for bonus points, and where they completely ignored repeated emails about serious service failings at 2 specific properties I give up. I get much more professional top-tier status treatment from Starwood and Hilton, whilst Accor are even worse than IHG.
Adieu.