You'll need to contact Billing, not sure CS has the ability. But they can most certainly move accounts to a new Battlenet. You should be able to get the two old RAF accounts moved to a new Battlenet to free up room for the new accounts.

http://us.battle.net/wow/en/forum/topic/1921697530#8

http://us.battle.net/wow/en/forum/topic/2548786155#3

http://us.battle.net/wow/en/forum/topic/2112374424#2