No, but they have responsibility to bring working game. There are no legal agreements which protects only seller but gives no rights to buyer. That is against the law.
I have no problems with Bioware making changes to game, they can bring new contents, new updates, etc but it shouldn't affect my gameplay experience. If I can't even play properly and seller demands money for a service which is not properly given, that will be against law. It doesn't matter what they wrote in their EULAs. Yes, basically we are paying to use their servers and characters which reside on their server but if we can't play, then there is no reason to pay?
I am not demanding any money or try to sue them for not able to play for 1-2 days but at least they can add more playtime to all subscribers until they fix their servers and bugs.