Join Date: Oct 2006
Location: London, UK
Programs: BA Gold, VS Silver, SQ Silver, IHG Plat Amb, Hilton Gold, Marriott Plat, Accor Silver, Radisson Prem
Posts: 16,872
March 15 is not very far away, so I wouldn't be surprised that there's no availability.
If there is availability but the system won't let you book online, then pick up the good old fashioned telephone.